Generative deep fields : arbitrarily sized, random synthetic astronomical images through deep learning

© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.Generative Adversarial Networks (GANs) are a class of artificial neural network that can produce realistic, but artificial, images that resemble those in a training set. In typical GAN architectures these images are small, but a variant known as Spatial-GANs (SGANs) can generate arbitrarily large images, provided training images exhibit some level of periodicity. Deep extragalactic imaging surveys meet this criteria due to the cosmological tenet of isotropy. Here we train an SGAN to generate images resembling the iconic Hubble Space Telescope eXtreme Deep Field (XDF). We show that the properties of 'galaxies' in generated images have a high level of fidelity with galaxies in the real XDF in terms of abundance, morphology, magnitude distributions and colours. As a demonstration we have generated a 7.6-billion pixel 'generative deep field' spanning 1.45 degrees. The technique can be generalised to any appropriate imaging training set, offering a new purely data-driven approach for producing realistic mock surveys and synthetic data at scale, in astrophysics and beyond.Peer reviewe

Predictors of admission and readmission to hospital for major depression: A community cohort study of 52,990 individuals.

Background Our current knowledge about predictors of admission and re-admission to hospital as a result of major depressive disorder (MDD) is limited. Here we present a descriptive analysis of factors which are associated with MDD hospitalisations within a large population cohort. Methods We linked participants of the Scottish Health Survey (SHS) to historical and prospective hospital admission data. We combined information from the SHS baseline interview and historical hospitalisations to define a range of exposure variables. The main outcomes of interest were: (1) first time admission for MDD occurring after the SHS interview; and (2) readmission for MDD. We used Cox regression to determine the association between each predictor and each outcome, after adjusting for age, gender and deprivation quintile. Results 52,990 adult SHS participants were included. During a median follow-up of 4.5 years per participant, we observed 530 first-time admissions for MDD. A relatively wide range of factors – encompassing social, individual health status, and lifestyle-related exposures – were associated with this outcome (p&#60;0.05). Among the 530 participants exhibiting a de novo admission for MDD during follow-up, 118 were later re-admitted. Only older age (over 70) and a prior non-depression related psychiatric admission were associated with readmission for MDD. Limtations MDD was defined using records of International Classification of Disease hospital discharge codes rather than formal diagnostic assessments. Conclusion These findings have implications for mental health service organisation and delivery and should stimulate future research on predictive factors for admission and readmission in MDD.</p

The determinants of participation in a social program: Evidence from a prototypical job training program

This paper decomposes the participation process of a prototypical program into eligibility, awareness, application, acceptance and enrollment. With this decomposition, we determine the sources of unequal participation for different groups, and demonstrate that variables often have very different effects at different stages in the participation process. Our analysis shows that personal choices substantially affect participation and that awareness of program eligibility is a major source of variation in participation.Social program participation; job training performance standards; cream skimming; job training partnership act (JTPA)

A very low frequency radio astronomy observatory on the Moon

Because of terrestrial ionospheric absorption, very little is known of the radio sky beyond 10 m wavelength. An extremely simple, low cost very low frequency radio telescope is proposed, consisting of a large array of short wires laid on the lunar surface, each wire equipped with an amplifier and a digitizer, and connected to a common computer. The telescope could do simultaneous multifrequency observations of much of the visible sky with high resolution in the 10 to 100 m wavelength range, and with lower resolution in the 100 to 1000 m range. It would explore structure and spectra of galactic and extragalactic point sources, objects, and clouds, and would produce detailed quasi-three-dimensional mapping of interstellar matter within several thousand parsecs of the Sun

Immigrant Entrepreneurs in the Massachusetts Biotechnology Industry (2007)

Immigrant entrepreneurs are co-founders in 25.7 percent of Massachusetts Biotechnology firms. In 2006, these immigrant-founded biotechnology companies produced over $7.6 billion dollars in sales and employed over 4,000 workers. The foreign-born founders came from across the globe but in larger numbers from Europe, Canada or Asia. Their firms specialize in the most complex, risky, life science-intensive aspects of biotechnology to seek knowledge directly applicable to human health. Biotechnology is a crucial industry for Massachhusetts and the evidence strongly suggests that immigrants have been key contributors to this industry by establishing new businesses as well as bringing intellectual capital and thereby contributing significantly to the overall economic growth of the Commonwealth

The Determinants of Participation in a Social Program: Evidence from a Prototypical Job Training Program

This paper decomposes the participation process of a prototypical program into eligibility, awareness, application, acceptance and enrollment. With this decomposition, we determine the sources of unequal participation for different groups, and demonstrate that variables often have very different effects at different stages in the participation process. Our analysis shows that personal choices substantially affect participation and that awareness of program eligibility is a major source of variation in participation.