Sleep Deprivation and Advice Taking

This is the final version. Available on open access from Nature Research via the DOI in this recordJudgements and decisions in many political, economic or medical contexts are often made while sleep deprived. Furthermore, in such contexts individuals are required to integrate information provided by – more or less qualified – advisors. We asked if sleep deprivation affects advice taking. We conducted a 2 (sleep deprivation: yes vs. no) ×2 (competency of advisor: medium vs. high) experimental study to examine the effects of sleep deprivation on advice taking in an estimation task. We compared participants with one night of total sleep deprivation to participants with a night of regular sleep. Competency of advisor was manipulated within subjects. We found that sleep deprived participants show increased advice taking. An interaction of condition and competency of advisor and further post-hoc analyses revealed that this effect was more pronounced for the medium competency advisor compared to the high competency advisor. Furthermore, sleep deprived participants benefited more from an advisor of high competency in terms of stronger improvement in judgmental accuracy than well-rested participants.Volkswagen Foundatio

Machine-learning of atomic-scale properties based on physical principles

We briefly summarize the kernel regression approach, as used recently in materials modelling, to fitting functions, particularly potential energy surfaces, and highlight how the linear algebra framework can be used to both predict and train from linear functionals of the potential energy, such as the total energy and atomic forces. We then give a detailed account of the Smooth Overlap of Atomic Positions (SOAP) representation and kernel, showing how it arises from an abstract representation of smooth atomic densities, and how it is related to several popular density-based representations of atomic structure. We also discuss recent generalisations that allow fine control of correlations between different atomic species, prediction and fitting of tensorial properties, and also how to construct structural kernels---applicable to comparing entire molecules or periodic systems---that go beyond an additive combination of local environments

Inherited multicentric osteolysis: case report of three siblings treated with bisphosphonate

Inherited Multicentric Osteolysis (IMO) is an uncommon familial condition of idiopathic pathophysiology causing bone osteolysis and dysplasia. These patients present with common rheumatologic complaints of pain, dysfunction and disability, and are often initially misdiagnosed as a chronic rheumatic disease of childhood such as juvenile idiopathic arthritis. We report a case of three siblings diagnosed with IMO. Diagnosis was made during childhood, with each sibling having different manifestations and course of disease. One had a previous history of bilateral hip dysplasia. Two had osteolysis of the foot, distal tibia and femur (lower limb bones), whilst one had osteolysis of the rib and unusual clavicular fractures. Unusually, all siblings appear to experience decreased pain sensation compared to norms. All siblings were treated with bisphosphonates and experienced a rapid improvement in pain symptoms, decreased analgesic requirements. Two had bone mineral density testing performed and both had increases post-bisphosphonate. In all three, there was subjective evidence of stabilisation of bone disease. Testing for matrix metalloproteinase-2 (MMP2) gene was negative

The central image of a gravitationally lensed quasar

A galaxy can act as a gravitational lens, producing multiple images of a background object. Theory predicts there should be an odd number of images but, paradoxically, almost all observed lenses have 2 or 4 images. The missing image should be faint and appear near the galaxy's center. These ``central images'' have long been sought as probes of galactic cores too distant to resolve with ordinary observations. There are five candidates, but in one case the third image is not necessarily a central image, and in the others, the central component might be a foreground source rather than a lensed image. Here we report the most secure identification of a central image, based on radio observations of PMN J1632-0033, one of the latter candidates. Lens models incorporating the central image show that the mass of the lens galaxy's central black hole is less than 2 x 10^8 M_sun, and the galaxy's surface density at the location of the central image is more than 20,000 M_sun per square parsec, in agreement with expectations based on observations of galaxies hundreds of times closer to the Earth.Comment: Nature, in press [7 pp, 2 figs]. Standard media embargo applies before publicatio

The Hubble Constant from Observations of the Brightest Red Giant Stars in a Virgo-Cluster Galaxy

The Virgo and Fornax clusters of galaxies play central roles in determining the Hubble constant H_0. A powerful and direct way of establishing distances for elliptical galaxies is to use the luminosities of the brightest red-giant stars (the TRGB luminosity, at M_I = -4.2). Here we report the direct observation of the TRGB stars in a dwarf elliptical galaxy in the Virgo cluster. We find its distance to be 15.7 +- 1.5 Megaparsecs, from which we estimate a Hubble constant of H_0 = 77 +- 8 km/s/Mpc. Under the assumption of a low-density Universe with the simplest cosmology, the age of the Universe is no more than 12-13 billion years.Comment: 12 pages, LaTeX, with 2 postscript figures; in press for Nature, July 199

Clues from nearby galaxies to a better theory of cosmic evolution

The great advances in the network of cosmological tests show that the relativistic Big Bang theory is a good description of our expanding universe. But the properties of nearby galaxies that can be observed in greatest detail suggest a still better theory would more rapidly gather matter into galaxies and groups of galaxies. This happens in theoretical ideas now under discussion.Comment: published in Natur

The morphologies of massive galaxies at 1 < z < 3 in the CANDELS-UDS field : compact bulges, and the rise and fall of massive discs

We have used high-resolution, Hubble Space Telescope, near-infrared imaging to conduct a detailed analysis of the morphological properties of the most massive galaxies at high redshift, modelling the WFC3/IR H-160-band images of the similar or equal to 200 galaxies in the CANDELS-UDS field with photometric redshifts 1 10(11)M(circle dot). We have explored the results of fitting single-Sersic and bulge+disc models, and have investigated the additional errors and potential biases introduced by uncertainties in the background and the on-image point spread function. This approach has enabled us to obtain formally acceptable model fits to the WFC3/IR images of > 90 per cent of the galaxies. Our results indicate that these massive galaxies at 1 2 the compact bulges display effective radii a factor of similar or equal to 4 smaller than local ellipticals of comparable mass. These trends also appear to extend to the bulge components of disc-dominated galaxies. In addition, we find that, while such massive galaxies at low redshift are generally bulge-dominated, at redshifts 1 2 they are mostly disc-dominated. The majority of the disc-dominated galaxies are actively forming stars, although this is also true for many of the bulge-dominated systems. Interestingly, however, while most of the quiescent galaxies are bulge-dominated, we find that a significant fraction (25-40 per cent) of the most quiescent galaxies, with specific star formation rates sSFR < 10(-10) yr(-1), have disc-dominated morphologies. Thus, while our results show that the massive galaxy population is undergoing dramatic changes at this crucial epoch, they also suggest that the physical mechanisms which quench star formation activity are not simply connected to those responsible for the morphological transformation of massive galaxies into present-day giant ellipticals

Accreting Protoplanets in the LkCa 15 Transition Disk

Exoplanet detections have revolutionized astronomy, offering new insights into solar system architecture and planet demographics. While nearly 1900 exoplanets have now been discovered and confirmed, none are still in the process of formation. Transition discs, protoplanetary disks with inner clearings best explained by the influence of accreting planets, are natural laboratories for the study of planet formation. Some transition discs show evidence for the presence of young planets in the form of disc asymmetries or infrared sources detected within their clearings, as in the case of LkCa 15. Attempts to observe directly signatures of accretion onto protoplanets have hitherto proven unsuccessful. Here we report adaptive optics observations of LkCa 15 that probe within the disc clearing. With accurate source positions over multiple epochs spanning 2009 - 2015, we infer the presence of multiple companions on Keplerian orbits. We directly detect H{\alpha} emission from the innermost companion, LkCa 15 b, evincing hot (~10,000 K) gas falling deep into the potential well of an accreting protoplanet.Comment: 35 pages, 3 figures, 1 table, 9 extended data item

Searches for Gravitational Waves from Binary Neutron Stars: A Review

A new generation of observatories is looking for gravitational waves. These waves, emitted by highly relativistic systems, will open a new window for ob- servation of the cosmos when they are detected. Among the most promising sources of gravitational waves for these observatories are compact binaries in the final min- utes before coalescence. In this article, we review in brief interferometric searches for gravitational waves emitted by neutron star binaries, including the theory, instru- mentation and methods. No detections have been made to date. However, the best direct observational limits on coalescence rates have been set, and instrumentation and analysis methods continue to be refined toward the ultimate goal of defining the new field of gravitational wave astronomy.Comment: 30 pages, 5 Figures, to appear in "Short-Period Binary Stars: Observations, Analyses, and Results", Ed.s Eugene F. Milone, Denis A. Leahy, David W. Hobil