Performance enhancement of a wideband spiral antenna using a stepped ground plane

This study presents the use of a stepped ground plane as a means to increase the gain and front-to-back ratio of an Archimedean spiral which operates in the frequency range 3–10 GHz. The backing structure is designed to optimize the antenna performance in discrete 1 GHz bands by placing each of the eight metal steps one quarter wavelength below the corresponding active regions of the spiral. Simulated and experimental results show that this type of ground plane can be designed to enhance the antenna performance over the entire 105% operating bandwidth of the spiral.

Monogamy and ground-state entanglement in highly connected systems

We consider the ground-state entanglement in highly connected many-body systems consisting of harmonic oscillators and spin-1/2 systems. Varying their degree of connectivity, we investigate the interplay between the enhancement of entanglement, due to connections, and its frustration, due to monogamy constraints. Remarkably, we see that in many situations the degree of entanglement in a highly connected system is essentially of the same order as in a low connected one. We also identify instances in which the entanglement decreases as the degree of connectivity increases.

The challenge to health professionals when carers resist truth telling at the end of life: a qualitative secondary analysis

Aims and objectives: To draw out the similar complexities faced by staff around
truth-telling in a children’s and adult population and to interrogate the dilemmas faced by staff when informal carers act to block truth-telling.

Background: Policy encourages normalisation of death, but carers may act to protect or prevent the patient from being told the truth. Little is known about the impact on staff.

Design: Secondary analysis of data using a supra-analysis design to identify commonality of experiences.

Methods: Secondary ‘supra-analysis’ was used to transcend the focus of two primary studies in the UK, which examined staff perspectives in a palliative children’s and a palliative adult setting, respectively. The analysis examined new theoretical questions relating to the commonality of issues independently derived in each primary study. Both primary studies used focus groups. Existing empirical data were analysed thematically and compared across the studies.

Results: Staff reported a hiding of the truth by carers and sustained use of activities aimed at prolonging life. Carers frequently ignored the advance of end of life, and divergence between staff and carer approaches to truth-telling challenged professionals. Not being truthful with patients had a deleterious effect on staff, causing anger and feelings of incompetence.

Conclusions: Both children’s and adult specialist palliative care staff found themselves caught in a dilemma, subject to policies that promoted openness in planning for death and informal carers who often prevented them from being truthful with patients about terminal prognosis. This dilemma had adverse psychological effects upon many staff.

Relevance to clinical practice: There remains a powerful death-denying culture in
many societies, and carers of dying patients may prevent staff from being truthful with their patients. The current situation is not ideal, and open discussion of this problem is the essential first step in finding a solution.

Coupling ground and airborne geophysical data with upscaling techniques for regional groundwater modeling of heterogeneous aquifers: Case study of a sedimentary aquifer intruded by volcanic dykes in Northern Ireland

In highly heterogeneous aquifer systems, conceptualization of regional groundwater flow models frequently results in the generalization or negligence of aquifer heterogeneities, both of which may result in erroneous model outputs. The calculation of equivalence related to hydrogeological parameters and applied to upscaling provides a means of accounting for measurement scale information but at regional scale. In this study, the Permo-Triassic Lagan Valley strategic aquifer in Northern Ireland is observed to be heterogeneous, if not discontinuous, due to subvertical trending low-permeability Tertiary dolerite dykes. Interpretation of ground and aerial magnetic surveys produces a deterministic solution to dyke locations. By measuring relative permeabilities of both the dykes and the sedimentary host rock, equivalent directional permeabilities, that determine anisotropy calculated as a function of dyke density, are obtained. This provides parameters for larger scale equivalent blocks, which can be directly imported to numerical groundwater flow models. Different conceptual models with different degrees of upscaling are numerically tested and results compared to regional flow observations. Simulation results show that the upscaled permeabilities from geophysical data allow one to properly account for the observed spatial variations of groundwater flow, without requiring artificial distribution of aquifer properties. It is also found that an intermediate degree of upscaling, between accounting for mapped field-scale dykes and accounting for one regional anisotropy value (maximum upscaling) provides results the closest to the observations at the regional scale.

Experimental linear-optics simulation of multipartite non-locality in the ground state of a quantum Ising ring

Critical phenomena involve structural changes in the correlations of its constituents. Such changes can be reproduced and characterized in quantum simulators able to tackle medium-to-large-size systems. We demonstrate these concepts by engineering the ground state of a three-spin Ising ring by using a pair of entangled photons. The effect of a simulated magnetic field, leading to a critical modification of the correlations within the ring, is analysed by studying two- and three-spin entanglement. In particular, we connect the violation of a multipartite Bell inequality with the amount of tripartite entanglement in our ring.

Old truths and new politics:Does truth commission 'publicness' impact democratization?

This article analyzes the relationship between truth and politics by asking whether the 'publicness' of a truth commission - defined by whether it has public hearings, releases a public report, and names perpetrators - contributes to democratization. The article reviews scholarship relevant to the potential democratizing effects of truth commissions and derives mechanisms that help explain this relationship. Work from the transitional justice field as well as democratization and political transition more generally is considered. Using a newly-constructed Truth Commission Publicness Dataset (TCPD), the analysis finds that even after statistically controlling for initial levels of democracy, democratic trends in the years prior to a commission, level of wealth, amnesties and/or trials, the influence of the South African Truth and Reconciliation Commission, and different cutoff points for measuring democratization across a number of models, more publicness predicts higher levels of democracy years after the commission has finished its work. The more public a truth commission is, the more it will contribute to democratization. The finding that more public truth commissions are associated with higher levels of democratization indicates particular strategies that policymakers, donors, and civil society activists may take to improve prospects for democracy in a country planning a truth commission in the wake of violence and/or government abuse. © The Author(s) 2012.

Does chemical composition of individual Scots pine trees determine the biodiversity of their associated ground vegetation?

Despite plant secondary metabolites being major determinants of species interactions and ecosystem processes, their role in the maintenance of biodiversity has received little attention. In order to investigate the relationship between chemical and biological diversity in a natural ecosystem, we considered the impact of chemical diversity in individual Scots pine trees (Pinus sylvestris) on species richness of associated ground vegetation. Scots pine trees show substantial genetically determined constitutive variation between individuals in concentrations of a group of secondary metabolites, the monoterpenes. When the monoterpenes of particular trees were assessed individually, there was no relationship with species richness of associated ground flora. However, the chemical diversity of monoterpenes of individual trees was significantly positively associated with the species richness of the ground vegetation beneath each tree, mainly the result of an effect among the non-woody vascular plants. This correlation suggests that the chemical diversity of the ecosystem dominant species has an important role in shaping the biodiversity of the associated plant community. The extent and significance of this effect, and its underlying processes require further investigation.