The classical double copy for Taub-NUT spacetime

The double copy is a much-studied relationship between gauge theory and gravity amplitudes. Recently, this was generalised to an infinite family of classical solutions to Einstein's equations, namely stationary Kerr-Schild geometries. In this paper, we extend this to the Taub-NUT solution in gravity, which has a double Kerr-Schild form. The single copy of this solution is a dyon, whose electric and magnetic charges are related to the mass and NUT charge in the gravity theory. Finally, we find hints that the classical double copy extends to curved background geometries.Comment: 13 pages, no figures. Minor edits to match journal versio

Synthesis and properties of Co-doped titanate nanotubes and their optical sensitization with methylene blue

Here we report on a novel chemical route to synthesize homogenous cobalt doped titanate nanotubes (CoTNT), using an amorphous Co-doped precursor. The influence of the synthesis temperature, autoclave dwell time and metal doping on the structural and microstructural as well as on the optical properties of the synthesized titanate nanotubes is studied and discussed. The optical band gaps of the CoTNT samples are red shifted in comparison with the values determined for the undoped samples, such red shifts bringing the absorption edge of the CoTNT samples into the visible region. CoTNT materials also demonstrate particular high adsorption ability for methylene blue, the amount of the adsorbed dye being higher than the one predictable for a monolayer formation. This suggests the possibility of intercalation of the dye molecule between the TiO6 layers of the TNT structure. It is also shown that the methylene blue sensitized Co-doped nanostructures are highly stable under UV radiation and present a strong and broad absorption in the visible region.Comment: 31 pages, 3 tables, 7 figure

Fitting isochrones to open cluster photometric data III. Estimating metallicities from UBV photometry

The metallicity is a critical parameter that affects the correct determination fundamental characteristics stellar cluster and has important implications in Galactic and Stellar evolution research. Fewer than 10 % of the 2174 currently catalog open clusters have their metallicity determined in the literature. In this work we present a method for estimating the metallicity of open clusters via non-subjective isochrone fitting using the cross-entropy global optimization algorithm applied to UBV photometric data. The free parameters distance, reddening, age, and metallicity simultaneously determined by the fitting method. The fitting procedure uses weights for the observational data based on the estimation of membership likelihood for each star, which considers the observational magnitude limit, the density profile of stars as a function of radius from the center of the cluster, and the density of stars in multi-dimensional magnitude space. We present results of [Fe/H] for nine well-studied open clusters based on 15 distinct UBV data sets. The [Fe/H] values obtained in the ten cases for which spectroscopic determinations were available in the literature agree, indicating that our method provides a good alternative to determining [Fe/H] by using an objective isochrone fitting. Our results show that the typical precision is about 0.1 dex

A Quantitative Analysis of Gender Impact in Judgements of Offenders with Mental Illnesses

Purpose The purpose of this study is to examine the effect gender has on the public perceptions of offenders with mental health issues. The authors aim to understand how offenders with mental illness are viewed by the public so future information and practices can be implemented to further educate on the topic of mental illness. Research has shown that mental health education can be a pivotal part of reducing risk and crime among the mentally ill population. Design/methodology/approach This study applies a quantitative design using vignettes. There were four scenarios, two as controls, and two experimental variables to examine how responses differed depending on gender and mental health. Twenty statements then followed each vignette and participants were asked to share how much they aligned their opinions with each statement on a five-point Likert scale. The sample was comprised of 80 participants. Findings The findings of this study largely support the relevant literature on the topic of gender and mental illness in offenders. Overall, the public was the least supportive of female offenders with mental illness, followed by male offenders with mental illness, then male offenders and lastly the most support was directed towards female offenders. Therefore, the present study’s initial hypotheses are also supported in that female offenders will garner a more sympathetic reaction than their male counterparts. However, if female offenders have mental health issues, they are viewed more negatively than males. Research limitations/implications For future replication of this study, the authors consider that a larger and more gender-balanced sample size would increase the ecological validity of the findings. Despite this, the findings of this study do fall in line with the relevant literature. Therefore, suggesting perhaps that the gender of the sample does not affect the overall outcome of the results. Practical implications Education regarding mental health for the public should be implemented as research has found this effective in de-stigmatising and helping to create protective factors to reduce offending. More training is needed for professionals within the criminal justice system, including police personnel, to ensure they are better equipped to consider the needs and behaviours of mentally ill individuals. The authors suggest that mental health awareness should be taught as part of the education system in the UK to help de-stigmatise and share helpful resources. The prison system in the UK needs to be able to provide better treatment programmes for inmates with mental health issues as research shows this is the most effective form of treatment at reducing recidivism. Social implications The social implications of this study are that it aims to understand perceptions of mental illness, gender and offending and, therefore, use the conclusions drawn to inform what is needed to improve perceptions if necessary. De-stigmatising and acknowledging mental illness can allow for better access to appropriate treatment. Facilitating reintegration back into society, and, therefore, increasing peer support which has been shown to reduce reoffending rates within the mentally ill population. Originality/value There are very few research studies looking at the impact of both gender and mental illness on how offenders are perceived. Most relevant research tends to either pick one or the other and therefore the present study is unique. In addition, most established research looks at the perception of a specific population. Whereas the present study has used a small but broad UK participant sample which is likely to be more generalisable. Finally, the results of this research have been able to both meet the aims of the study and accept the proposed hypotheses

Empiricism and stochastics in cellular automaton modeling of urban land use dynamics

An increasing number of models for predicting land use change in regions of rapidurbanization are being proposed and built using ideas from cellular automata (CA)theory. Calibrating such models to real situations is highly problematic and to date,serious attention has not been focused on the estimation problem. In this paper, wepropose a structure for simulating urban change based on estimating land usetransitions using elementary probabilistic methods which draw their inspiration fromBayes' theory and the related ?weights of evidence? approach. These land use changeprobabilities drive a CA model ? DINAMICA ? conceived at the Center for RemoteSensing of the Federal University of Minas Gerais (CSR-UFMG). This is based on aneight cell Moore neighborhood approach implemented through empirical land useallocation algorithms. The model framework has been applied to a medium-size townin the west of São Paulo State, Bauru. We show how various socio-economic andinfrastructural factors can be combined using the weights of evidence approach whichenables us to predict the probability of changes between land use types in differentcells of the system. Different predictions for the town during the period 1979-1988were generated, and statistical validation was then conducted using a multipleresolution fitting procedure. These modeling experiments support the essential logicof adopting Bayesian empirical methods which synthesize various information aboutspatial infrastructure as the driver of urban land use change. This indicates therelevance of the approach for generating forecasts of growth for Brazilian citiesparticularly and for world-wide cities in general