Multipartite nonlocality in a thermalized Ising spin chain

We study multipartite correlations and nonlocality in an isotropic Ising ring under transverse magnetic field at both zero and finite temperature. We highlight parity-induced differences between the multipartite Bell-like functions used in order to quantify the degree of nonlocality within a ring state and reveal a mechanism for the passive protection of multipartite quantum correlations against thermal spoiling effects that is clearly related to the macroscopic properties of the ring model.

Lichen-induced biomodification of calcareous surfaces: Bioprotection versus biodeterioration

Studies demonstrate the active and passive capability of lichens to inhibit or retard the weathering of calcareous surfaces. Lichen coverage may actively protect a surface through shielding by the thallus and the binding and waterproofing of the rock surface and subsurface by fungal hyphae. Passive protection of rock surfaces may be induced by the formation of an insoluble encrustation, such as calcium oxalate, at the lichen-rock interface. Recent research suggests that the decay of hyphae, induced by changes in microenvironmental conditions, necrosis, parasitism or the natural physiological traits of particular lichen species, may expose a chemically and physically weakened substrate to dissolution triggering relatively rapid weathering-related surface lowering. Consequently, certain epilithic crustose and endolithic lichens may induce a period of surface stability throughout the course of their lifespan, followed by a phase of instability and rapid episodic microtopographical evolution after death and decay. A series of conceptual models is proposed to illustrate this idea over short (single lichen lifespan) and long (multiple lichen lifespans) timescales. The models suggest that the microscale biogeomorphological system of lichen-rock interaction is underpinned by nonlinear dynamical system theory as it exhibits dynamical instability and is consequently difficult to predict over a long timescale. Dominance by biodeterioration or bioprotection may be altered by changes in lichen species or in environmental conditions over time.

Passive Control of Plume Interference on Slender Axisymmetric Bodies

The physics of the plume-induced shock and separation, particularly at high plume to exit pressure ratios with and without shock-turbulent boundary-layer control methods, were studied using computational techniques. Mass-averaged Navier-Stokes equations with a two-equation turbulence model were solved by using a fully implicit finite volume scheme and time.marching algorithm. The control methodologies for shock interactions included a porous tail and a porous extension attached at the nozzle exit or trailing edge. The porous tail produced a weaker shock and fixed the shock position on the control surface. The effect of the porous extension on shock interactions was mainly to restrain the plume from strongly underexpanding during a change in flight conditions. These techniques could give an additional dimension to the design and control of supersonic missiles.

The Influence of Child Protection Orientation on Child Welfare Practice

This article reports the findings of the second part of a two-part research project examining the potential for social workers to make changes in their work with families and children. While social workers in the United Kingdom have been encouraged to shift from a child protection to a child welfare orientation in their practice, such changes have been hampered by professional and organisational concern to manage risk. The research explores the influence of a child protection orientation on practice in child welfare cases. The findings, from two file analyses and interviews with twenty-six social workers, indicate that such an influence is indeed apparent. This is evidenced in two ways; firstly patterns of practice in child welfare cases are similar to those in child protection cases. Secondly, while the majority of social workers express an attitudinal desire to move towards a child welfare orientation, they still prioritise the management of risk in their practice. It is argued that social workers need permission from their employing organisations to make changes in their practice. This, in turn, requires such organisations to state clear goals in line with a child welfare orientation and develop holistic strategies to achieve these.