Efficient high-dimensional entanglement imaging with a compressive sensing, double-pixel camera

We implement a double-pixel, compressive sensing camera to efficiently characterize, at high resolution, the spatially entangled fields produced by spontaneous parametric downconversion. This technique leverages sparsity in spatial correlations between entangled photons to improve acquisition times over raster-scanning by a scaling factor up to n^2/log(n) for n-dimensional images. We image at resolutions up to 1024 dimensions per detector and demonstrate a channel capacity of 8.4 bits per photon. By comparing the classical mutual information in conjugate bases, we violate an entropic Einstein-Podolsky-Rosen separability criterion for all measured resolutions. More broadly, our result indicates compressive sensing can be especially effective for higher-order measurements on correlated systems.Comment: 10 pages, 7 figure

The (Mis)appropriation of HIV/AIDS advocacy strategies in Global Mental Health: towards a more nuanced approach

Background: Mental health is increasingly finding a place on global health and international development agendas. Advocates for Global Mental Health (GMH), and international organizations such as the World Health Organization (WHO) and the World Bank, argue that treatments available in high-income countries should also be made available in low- and middle-income countries. Such arguments are often made by comparing mental health to infectious diseases, including the relative disease and economic burdens they impose, and pointing to the applicability of the right to access treatment for mental health, not only infectious diseases. HIV/AIDS advocacy in particular has been held up by GMH advocates as offering an appropriate strategy for generating global commitment. Discussion: There is a need to assess how health issues are framed not only in relation to social goods outside of health (such as human rights, security or development), but also in relation to other health or disease models, and how health policy and practice is shaped as a result. The article debates the merits and consequences of likening mental health to HIV/AIDS, and identifies four major problems with the model for GMH advocacy being developed through these analogies: 1. An inappropriately universalizing global approach to context-specific problems; 2. A conception of human rights that focuses on the right to access treatment at the expense of the right to refuse it; 3. A tendency to treat poverty as a psychiatric issue, rather than recognizing that mental distress can be the result of poverty and other forms of inequality; 4. The prioritization of destigmatization of disease over social justice models. Conclusion: There are significant problems with the wholesale adoption of an (often simplified) version of HIV/AIDS advocacy as a model for GMH. Yet critical engagement with the important and nuanced differences between HIV/AIDS and mental health may nevertheless point to some possibilities for productive engagement and cross-fertilisation between advocates, activists and scholars in both fields

Effects of simulated lightning on composite and metallic joints

The effects of simulated lightning strikes and currents on aircraft bonded joints and access/inspection panels were investigated. Both metallic and composite specimens were tested. Tests on metal fuel feed through elbows in graphite/epoxy structures were evaluated. Sparking threshold and residual strength of single lap bonded joints and sparking threshold of access/inspection panels and metal fuel feed through elbows are reported

On the Number of Nonnegative Solutions to the Inequality a1 +....ar < n

In this paper, we present a simple and fast method for counting the number of nonnegative integer solutions to the equality a1x1+a2x2+: : :+arxr = n where a1; a2; :::; ar and n are positive integers. As an application, we use the method for finding the number of solutions of a Diophantine inequality

'The risks of playing it safe': a prospective longitudinal study of response to reward in the adolescent offspring of depressed parents

BACKGROUND Alterations in reward processing may represent an early vulnerability factor for the development of depressive disorder. Depression in adults is associated with reward hyposensitivity and diminished reward seeking may also be a feature of depression in children and adolescents. We examined the role of reward responding in predicting depressive symptoms, functional impairment and new-onset depressive disorder over time in the adolescent offspring of depressed parents. In addition, we examined group differences in reward responding between currently depressed adolescents, psychiatric and healthy controls, and also cross-sectional associations between reward responding and measures of positive social/environmental functioning. Method We conducted a 1-year longitudinal study of adolescents at familial risk for depression (n = 197; age range 10-18 years). Reward responding and self-reported social/environmental functioning were assessed at baseline. Clinical interviews determined diagnostic status at baseline and at follow-up. Reports of depressive symptoms and functional impairment were also obtained. RESULTS Low reward seeking predicted depressive symptoms and new-onset depressive disorder at the 1-year follow-up in individuals free from depressive disorder at baseline, independently of baseline depressive symptoms. Reduced reward seeking also predicted functional impairment. Adolescents with current depressive disorder were less reward seeking (i.e. bet less at favourable odds) than adolescents free from psychopathology and those with externalizing disorders. Reward seeking showed positive associations with social and environmental functioning (extra-curricular activities, humour, friendships) and was negatively associated with anhedonia. There were no group differences in impulsivity, decision making or psychomotor slowing. CONCLUSIONS Reward seeking predicts depression severity and onset in adolescents at elevated risk of depression. Adaptive reward responses may be amenable to change through modification of existing preventive psychological interventions

Compressive Wavefront Sensing with Weak Values

We demonstrate a wavefront sensor based on the compressive sensing, single-pixel camera. Using a high-resolution spatial light modulator (SLM) as a variable waveplate, we weakly couple an optical field's transverse-position and polarization degrees of freedom. By placing random, binary patterns on the SLM, polarization serves as a meter for directly measuring random projections of the real and imaginary components of the wavefront. Compressive sensing techniques can then recover the wavefront. We acquire high quality, 256x256 pixel images of the wavefront from only 10,000 projections. Photon-counting detectors give sub-picowatt sensitivity