Quantum walks with encrypted data

In the setting of networked computation, data security can be a significant concern. Here we consider the problem of allowing a server to remotely manipulate client supplied data, in such a way that both the information obtained by the client about the server's operation and the information obtained by the server about the client's data are significantly limited. We present a protocol for achieving such functionality in two closely related models of restricted quantum computation -- the Boson sampling and quantum walk models. Due to the limited technological requirements of the Boson scattering model, small scale implementations of this technique are feasible with present-day technology.Comment: 4 pages, 2 figure

Psychological distress, self-harm and attempted suicide in UK 17-year olds: prevalence and sociodemographic inequalities

In a large (n = 10 103), nationally representative sample of 17-year-olds 16.1% had experienced high psychological distress in the past 30 days, 24.1% had self-harmed in the previous 12 months and 7.4% had ever attempted suicide. Females, White adolescents, sexual minorities and those from more socioeconomically disadvantaged families had worse mental health outcomes; with the exceptions of no detected differences in attempted suicide by ethnicity and in self-harm by socioeconomic position. Findings include a narrower gender gap in self-harm at age 17 (males 20.1%, females 28.2%) compared with at age 14 (males 8.5%; females 22.8%) and 2–4 times higher prevalence in sexual minority adolescents (39.3% high distress, 55.8% self-harmed, 21.7% attempted suicide compared with 13.4%, 20.5% and 5.8%, respectively, in heterosexual adolescents)

Development and predictors of mental ill-health and wellbeing from childhood to adolescence

PURPOSE: The aim is to investigate the (1) longitudinal development in mental ill-health and wellbeing from ages 11 to 14, (2) predictors of changes in mental health outcomes, and (3) sex and reporter differences. METHOD: Data are taken from 9553 participants in the Millennium Cohort Study, with both mental ill-health (parent- and self-report) and wellbeing outcomes of the cohort members measured at ages 11 and 14. A range of childhood socio-demographic, human capital, family and wider environment risk and protective factors are investigated. RESULTS: Wellbeing has weak stability and mental ill-health has moderate stability between ages 11 and 14 and large sex differences emerge in all the mental health outcomes investigated, with girls experiencing lower wellbeing and greater symptoms of mental illness at age 14. Raw associations between outcomes, and differences in their predictors, indicate varying patterns emerging for parent- and self-reported mental ill-health, with parent-reported symptoms in childhood a poor predictor of both self-reported wellbeing and depressive symptoms in adolescence. Investigating the emergent sex differences in prevalences highlights childhood risk and protective factors at this age that are more salient in females, including family income, school connectedness, cognitive ability, whereas peer relationships and bullying were equally relevant for mental health development in both males and females. CONCLUSION: Low–moderate stability of mental health outcomes stresses the importance of the transition period for mental health, highlighting an intervention window at these ages for prevention. Socio-economic status is associated with mental health development in females but not in males at this age, highlighting a sex-specific vulnerability of deprivation associated with poorer mental health in adolescent females

Rapid and robust spin state amplification

Electron and nuclear spins have been employed in many of the early demonstrations of quantum technology (QT). However applications in real world QT are limited by the difficulty of measuring single spins. Here we show that it is possible to rapidly and robustly amplify a spin state using a lattice of ancillary spins. The model we employ corresponds to an extremely simple experimental system: a homogenous Ising-coupled spin lattice in one, two or three dimensions, driven by a continuous microwave field. We establish that the process can operate at finite temperature (imperfect initial polarisation) and under the effects of various forms of decoherence.Comment: 5 pages, 2 figure

Reform of Education Tax Credit Provisions: Policy Considerations to Improve and Simply Benefits

This paper examines current law on the existing federal education tax credits and deductions used to pay post-secondary education costs as well as some of these reform proposals, including the 2005 Advisory Panel and 2010 National Commission’s recommendations as they relate to post-secondary education costs, as a basis for preparing tax reform recommendations to simplify the various education tax benefits. In addition, the authors propose a tax refund application that will assist taxpayers in repaying their federal student loans

Sex, ethnic and socioeconomic inequalities and trajectories in child and adolescent mental health in Australia and the UK: findings from national prospective longitudinal studies

BACKGROUND: This study investigates the sex, ethnic and socioeconomic inequalities in emotional difficulties over childhood and adolescence using longitudinal cohort studies in the UK and Australia. Estimating cross-national differences contributes to understanding of the consistency of inequalities in mental health across contexts. METHODS: Data from 19,748 participants in two contemporary representative samples in Australia (Growing Up in Australia: The Longitudinal Study of Australian Children, n = 4,975) and UK (Millennium Cohort Study, n = 14,773) were used. Emotional difficulties were assessed using the parent-reported Strengths and Difficulties Questionnaire at ages 4/5, 6/7, 11/12 and 14/15 years and the self-reported Short Moods and Feelings Questionnaire at age 14/15. Latent Growth Curve Modelling was used to examine mental health over time. RESULTS: There were significant increases in emotional difficulties in both countries over time. Emotional difficulties were higher in Australian children at all ages. The gender gap in self-reported depressive symptoms at age 14/15 was larger in the UK (8% of UK and 13% of Australian boys were above the depression cut-off, compared with 23% of girls). Ethnic minority children had higher emotional difficulties at age 4/5 years in both countries, but over time this difference was no longer observed in Australia. In the UK, this reversed whereby at ages 11/12 and 14/15 ethnic minority children had lower symptoms than their White majority peers. Socioeconomic differences were more marked based on parent education and employment status in Australia and by parent income in the UK. UK children, children from White majority ethnicity and girls evidenced steeper worsening of symptoms from age 4/5 to 14/15 years. CONCLUSIONS: Even in two fairly similar countries (i.e. English-speaking, high-income, industrialised), the observed patterns of inequalities in mental health symptoms based on sociodemographics are not the same. Understanding country and context-specific drivers of different inequalities provides important insights to help reduce disparities in child and adolescent mental health

miRNA-Mediated Regulation of Adult Hippocampal Neurogenesis; Implications for Epilepsy

Hippocampal neural stem/progenitor cells (NSPCs) proliferate and differentiate to generate new neurons across the life span of most mammals, including humans. This process takes place within a characteristic local microenvironment where NSPCs interact with a variety of other cell types and encounter systemic regulatory factors. Within this microenvironment, cell intrinsic gene expression programs are modulated by cell extrinsic signals through complex interactions, in many cases involving short non-coding RNA molecules, such as miRNAs. Here we review the regulation of gene expression in NSPCs by miRNAs and its possible implications for epilepsy, which has been linked to alterations in adult hippocampal neurogenesis

Selective ablation of thin films using ultra-short laser pulses

The micro processing of materials using ultra short pulse (USP) lasers with durations in the low picosecond (ps) and femtosecond (fs) range allows for the possibility of precision material removal on both nanometre and micron scales. Precision material removal can be achieved due to the near diffraction limited focus spot size and ultra-short pulse durations, which provide extremely high peak intensities with minimal thermal impact on the surrounding area. The work presented in this thesis is primarily concerned with the selective ablation of thin films deposited on various surfaces, using lasers with picosecond temporal pulse lengths at 1064 nm. As a result, damage to the substrate is negated through exploitation of the difference in linear absorption coefficients between the thin film and substrate. To elucidate the mechanism of selective processing with USP lasers; absorption, single and multi-pulse ablation effects were investigated in both fixed and variable beam positions. A sample of white float glass vacuum coated with indium tin oxide (ITO) was chosen as the material for this study. Experimental results demonstrate that linear absorption (α (λ)) of the ITO and substrate plays a key role in achieving selective thin film ablation. As a direct consequence of the difference in absorption coefficients at 1064 nm, the single (ϕ_th^1 ) and multi (ϕ_th^n ) pulse ablation thresholds of both materials are altered during the high peak intensity exposure. Selective processing was achieved by exploiting the difference between the ablation thresholds of ITO and glass. When irradiated with multiple pulses the ablation threshold of the substrate was observed to decrease with increasing pulse number. This change in threshold fundamentally limits the selective processing window; therefore incubation (S) effects must be considered when determining the viability of selective processing. For the purpose of practical applications, a series of case studies are also presented which attempt to utilise selective materials processing. These investigations were split into industrial and conservation. Industrial case studies focused on successfully micro processing a small thin film ITO circuit using a Spatial Light Modulator and a new low cost solar cell (F doped SnO2); whilst in conservation, the restoration of a pair of Royal gloves and the removal of unwanted bronze gilding is presented. The application of USP lasers in conservation represents a relatively new field of study where little previous research has been carried out. These case studies not only showcase the wide range of USP applications in which selective processing can be applied but also highlight the limitations of this method

Viability of laser cleaning of papyrus: Conservation and scientific assessment

There has been a growing interest in laser cleaning applications for a variety of organic materials such as paper, parchment, textiles, and leather during the last decade. However, archaeological organic materials, notably papyrus, have rarely been investigated. This contribution examines whether removal of burial encrustation can be justified in view of its short-term and long-term effects on the substrate. To examine this, tests using mock objects have been performed. Using artificially soiled and archaeological papyrus samples, optimization of laser cleaning parameters using a picosecond laser (1064 nm, various operating conditions) was attempted. Optimization was based on colorimetry, optical microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, and cellulose degree of polymerization data, both before and after accelerated degradation. In papyrus, there is no clear damage threshold, and substrate degradation can always be observed and is comparable in treated (cleaned) and untreated (soiled) objects. Therefore, the decision on whether to clean papyrus using lasers is predominantly based on aesthetic and treatability (e.g. need for consolidation) criteria