Diet Specialization by the Scarlet Kingsnake, Lampropeltis elapsoides (Colubridae)

Based on 34 natural prey items, Lampropeltis elapsoides eats primarily elongate squamates (97%), especially skinks (74%) and colubroid snakes (15%). N o ontogenetic or geographic variation is evident; prey items are swallowed headfirst and average 19% of predator mass. The diet substantially overlaps that of juveniles of some other lampropeltines, including sympatric L. triangulum, but is unusually narrow compared to adults of most other species

Diet Specialization by the Scarlet Kingsnake, Lampropeltis elapsoides (Colubridae)

Based on 34 natural prey items, Lampropeltis elapsoides eats primarily elongate squamates (97%), especially skinks (74%) and colubroid snakes (15%). N o ontogenetic or geographic variation is evident; prey items are swallowed headfirst and average 19% of predator mass. The diet substantially overlaps that of juveniles of some other lampropeltines, including sympatric L. triangulum, but is unusually narrow compared to adults of most other species

Modelling of dielectric barrier discharge plasma actuators for direct numerical simulations

In recent years the development of devices known as plasma actuators has advanced the promise of controlling flows in new ways that increase lift, reduce drag and improve aerodynamic efficiencies; advances that may lead to safer, more efficient and quieter aircraft. The large number of parameters (location of the actuator, orientation, size, relative placement of the embedded and exposed electrodes, materials, applied voltage, frequency) affecting the performance of plasma actuators makes their development, testing and optimisation a very complicated task. Several approaches have been proposed for developing numerical models for plasma actuators. The discharge can be modelled by physics-based kinetic methods based on first principles, by semi-empirical phenomenological approaches and by PIV-based methods where the discharge is replaced by a steady-state body force. The latter approach receives a recent interest for its easy implementation in RANS and U-RANS solvers. Here, a forcing term extracted from experiments is implemented into our high-order Navier-Stokes solver (DNS) in order to evaluate its robustness and ability to mimic the effects of a surface dielectric barrier discharge. This experimental forcing term is compared to the numerical forcing term developed by Suzen & Huang (1, 2) with an emphasis on the importance of the wall-normal component of each model

Dynamics of Transformation from Segregation to Mixed Wealth Cities

We model the dynamics of the Schelling model for agents described simply by a continuously distributed variable - wealth. Agents move to neighborhoods where their wealth is not lesser than that of some proportion of their neighbors, the threshold level. As in the case of the classic Schelling model where segregation obtains between two races, we find here that wealth-based segregation occurs and persists. However, introducing uncertainty into the decision to move - that is, with some probability, if agents are allowed to move even though the threshold level condition is contravened - we find that even for small proportions of such disallowed moves, the dynamics no longer yield segregation but instead sharply transition into a persistent mixed wealth distribution. We investigate the nature of this sharp transformation between segregated and mixed states, and find that it is because of a non-linear relationship between allowed moves and disallowed moves. For small increases in disallowed moves, there is a rapid corresponding increase in allowed moves, but this tapers off as the fraction of disallowed moves increase further and finally settles at a stable value, remaining invariant to any further increase in disallowed moves. It is the overall effect of the dynamics in the initial region (with small numbers of disallowed moves) that shifts the system away from a state of segregation rapidly to a mixed wealth state. The contravention of the tolerance condition could be interpreted as public policy interventions like minimal levels of social housing or housing benefit transfers to poorer households. Our finding therefore suggests that it might require only very limited levels of such public intervention - just sufficient to enable a small fraction of disallowed moves, because the dynamics generated by such moves could spur the transformation from a segregated to mixed equilibrium.Comment: 12 pages, 7 figure

School violence, school differences and school discourses

This article highlights one strand of a study which investigated the concept of the violenceresilient school. In six inner-city secondary schools, data on violent incidents in school and violent crime in the neighbourhood were gathered, and compared with school practices to minimise violence, accessed through interviews. Some degree of association between the patterns of behaviour and school practices was found: schools with a wider range of wellconnected practices seemed to have less difficult behaviour. Interviews also showed that the different schools had different organisational discourses for construing school violence, its possible causes and the possible solutions. Differences in practices are best understood in connection with differences in these discourses. Some of the features of school discourses are outlined, including their range, their core metaphor and their silences. We suggest that organisational discourse is an important concept in explaining school effects and school differences, and that improvement attempts could have clearer regard to this concept