Non-Equilibrium Surface Tension of the Vapour-Liquid Interface of Active Lennard-Jones Particles

We study a three-dimensional system of self-propelled Brownian particles interacting via the Lennard-Jones potential. Using Brownian Dynamics simulations in an elongated simulation box, we investigate the steady states of vapour-liquid phase coexistence of active Lennard-Jones particles with planar interfaces. We measure the normal and tangential components of the pressure tensor along the direction perpendicular to the interface and verify mechanical equilibrium of the two coexisting phases. In addition, we determine the non-equilibrium interfacial tension by integrating the difference of the normal and tangential component of the pressure tensor, and show that the surface tension as a function of strength of particle attractions is well-fitted by simple power laws. Finally, we measure the interfacial stiffness using capillary wave theory and the equipartition theorem, and find a simple linear relation between surface tension and interfacial stiffness with a proportionality constant characterized by an effective temperature.Comment: 12 pages, 5 figures (Corrected typos and References

Crystallization in suspensions of hard spheres: A Monte Carlo and Molecular Dynamics simulation study

The crystallization of a metastable melt is one of the most important non equilibrium phenomena in condensed matter physics, and hard sphere colloidal model systems have been used for several decades to investigate this process by experimental observation and computer simulation. Nevertheless, there is still an unexplained discrepancy between simulation data and experimental nucleation rate densities. In this paper we examine the nucleation process in hard spheres using molecular dynamics and Monte Carlo simulation. We show that the crystallization process is mediated by precursors of low orientational bond-order and that our simulation data fairly match the experimental data sets

Motivation and coping with the stress of assessment: Gender differences in outcomes for university students

The main objectives of the present research were to test a conceptual model linking motivational processes involved in coping with the stress of university assessment, and to examine gender differences in these processes. Self-determined motivation was hypothesized to predict coping strategies and the response to assessment-related stress, and coping was hypothesized to play a considerable role in short- and long-term outcomes of assessment. We examined this model using multiple group path analysis. In Study 1 (N = 265), music students’ use of engagement-coping strategies led to stronger musical career intentions, while disengagement-coping strategies led to weaker intentions. In Study 2 (N = 340), students’ increased use of engagement coping, and decreased use of disengagement coping strategies led to higher grades, higher positive affect and lower negative affect. In both studies, engagement and disengagement-coping were predicted by autonomous and controlled motivation, respectively. Motivation also indirectly predicted academic outcomes through stress appraisal and coping. While women experienced higher levels of stress, men were more negatively affected by the use of disengagement-oriented coping. Gender differences were also found on the links between engagement-oriented coping and outcomes. These results fill an important gap in the literature regarding gender differences in the outcomes coping in education, as well as contributing to a better understanding of the processes linking motivation, coping and academic outcomes

Orbital and spin physics in LiNiO2 and NaNiO2

We derive a spin-orbital Hamiltonian for a triangular lattice of e_g orbital degenerate (Ni^{3+}) transition metal ions interacting via 90 degree superexchange involving (O^{2-}) anions, taking into account the on-site Coulomb interactions on both the anions and the transition metal ions. The derived interactions in the spin-orbital model are strongly frustrated, with the strongest orbital interactions selecting different orbitals for pairs of Ni ions along the three different lattice directions. In the orbital ordered phase, favoured in mean field theory, the spin-orbital interaction can play an important role by breaking the U(1) symmetry generated by the much stronger orbital interaction and restoring the threefold symmetry of the lattice. As a result the effective magnetic exchange is non-uniform and includes both ferromagnetic and antiferromagnetic spin interactions. Since ferromagnetic interactions still dominate, this offers yet insufficient explanation for the absence of magnetic order and the low-temperature behaviour of the magnetic susceptibility of stoichiometric LiNiO_2. The scenario proposed to explain the observed difference in the physical properties of LiNiO_2 and NaNiO_2 includes small covalency of Ni-O-Li-O-Ni bonds inducing weaker interplane superexchange in LiNiO_2, insufficient to stabilize orbital long-range order in the presence of stronger intraplane competition between superexchange and Jahn-Teller coupling.Comment: 33 pages, 12 postscript figures, uses iopams.sty . This article features in New Journal of Physics as part of a Focus Issue on Orbital Physics - all contributions may be freely accessed at (http://stacks.iop.org/1367-2630/6/i=1/a=E05). The published version of this article may be found at http://stacks.iop.org/1367-2630/7/12

FlyBase 101 – the basics of navigating FlyBase

FlyBase (http://flybase.org) is the leading database and web portal for genetic and genomic information on the fruit fly Drosophila melanogaster and related fly species. Whether you use the fruit fly as an experimental system or want to apply Drosophila biological knowledge to another field of study, FlyBase can help you successfully navigate the wealth of available Drosophila data. Here, we review the FlyBase web site with novice and less-experienced users of FlyBase in mind and point out recent developments stemming from the availability of genome-wide data from the modENCODE project. The first section of this paper explains the organization of the web site and describes the report pages available on FlyBase, focusing on the most popular, the Gene Report. The next section introduces some of the search tools available on FlyBase, in particular, our heavily used and recently redesigned search tool QuickSearch, found on the FlyBase homepage. The final section concerns genomic data, including recent modENCODE (http://www.modencode.org) data, available through our Genome Browser, GBrowse

International experience of public infrastructure delivery in support of housing growth

This paper compares planning and funding arrangements for public infrastructure delivery in support of new housing development in the UK, Australia, Germany, the Netherlands, Canada, the US, and Hong Kong/Mainland China. It examines the roles and responsibilities of different levels of government, the extraction of financial contributions from the development process (mainly funded through increases in land value), and the level of involvement of private and public actors in infrastructure delivery and land value capture (LVC). Three linked questions provide a basis for comparison of the cases: first, what arrangements are in place, in terms of planning hierarchy and responsibility, for coordinating infrastructure delivery (and how do these relate to funding arrangements); second, how are local contributions extracted from the development process or through the acquisition and sale of land; and lastly, what inferences can be drawn regarding the relative power of public and private actors in this process and to what extent is public interest prioritized/served through prevailing approaches to value extraction. The paper contributes international experience to debates on optimizing planning approaches for infrastructure delivery while maximizing public benefit from land value

Obsessive passion: a compensatory response to unsatisfied needs

The present research investigated the role of two sources of psychological need satisfaction (inside and outside a passionate activity) as determinants of harmonious (HP) and obsessive (OP) passion. Four studies were carried out with different samples of young and middle-aged adults (e.g., athletes, musicians; total N=648). Different research designs (cross-sectional, mixed, longitudinal) were also used. Results showed that only a rigid engagement in a passionate activity (OP) was predicted by low levels of need satisfaction outside the passionate activity (in an important life context or in life in general), whereas both OP and a more favorable and balanced type of passion, HP were positively predicted by need satisfaction inside the passionate activity. Further, OP led to negative outcomes, and HP predicted positive outcomes. These results suggest that OP may represent a form of compensatory striving for psychological need satisfaction. It appears important to consider two distinct sources of need satisfaction, inside and outside the passionate activity, when investigating determinants of optimal and less optimal forms of activity engagemen

Исторический роман о Максиме Греке и его место в творчестве Мицоса Александропулоса

Целью статьи является анализ творчества Мицоса Александропулоса (Αλεξανδρόπουλος Μήτσος, 1924- 2008) в контексте развития современного греческого исторического романа (на примере романа «Сцены из жизни Максима Грека» («Σκηνές από το βίο του Μάξιμου του Γραικού», 1967-1969))