Cadmium sulfide in a Mesoproterozoic terrestrial environment

Peer reviewedPostprin

Information theoretic approach to interactive learning

The principles of statistical mechanics and information theory play an important role in learning and have inspired both theory and the design of numerous machine learning algorithms. The new aspect in this paper is a focus on integrating feedback from the learner. A quantitative approach to interactive learning and adaptive behavior is proposed, integrating model- and decision-making into one theoretical framework. This paper follows simple principles by requiring that the observer's world model and action policy should result in maximal predictive power at minimal complexity. Classes of optimal action policies and of optimal models are derived from an objective function that reflects this trade-off between prediction and complexity. The resulting optimal models then summarize, at different levels of abstraction, the process's causal organization in the presence of the learner's actions. A fundamental consequence of the proposed principle is that the learner's optimal action policies balance exploration and control as an emerging property. Interestingly, the explorative component is present in the absence of policy randomness, i.e. in the optimal deterministic behavior. This is a direct result of requiring maximal predictive power in the presence of feedback.Comment: 6 page

Hematological response in sheep given protracted exposures to Co 60 gamma radiation

Leukocyte count changes in sheep after prolonged exposure to gamma irradiation at rate of 1.9 R/h

Late Ediacaran life on land: desiccated microbial mats and large biofilm streamers

Acknowledgments SM acknowledges support from the European Union’s Horizon 2020 Research and Innovation Programme under Marie Skłodowska-Curie grant agreement 747877, and from the NASA Astrobiology Institute NNA13AA90A, Foundations of Complex Life, Evolution, Preservation and Detection on Earth and Beyond. JJM recognised funding from Novas Consulting, through the Geological Society of London, as well as from the Government of Newfoundland and Labrador. We thank B. Lynne and J. Poling for help in obtaining panels A, C and D of Figure 4. Discussions with D. McIlroy and P. Smith, and the comments of William McMahon (no relation to SM) and three anonymous reviewers, significantly improved this work. We thank the people of Ferryland for their continued support and hospitality. The early stages of this research benefited greatly from the guidance of M. D. Brasier.Peer reviewedPostprin

KIC 9406652: An Unusual Cataclysmic Variable in the Kepler Field of View

KIC 9406652 is a remarkable variable star in the Kepler field of view that shows both very rapid oscillations and long term outbursts in its light curve. We present an analysis of the light curve over quarters 1 to 15 and new spectroscopy that indicates that the object is a cataclysmic variable with an orbital period of 6.108 hours. However, an even stronger signal appears in the light curve periodogram for a shorter period of 5.753 hours, and we argue that this corresponds to the modulation of flux from the hot spot region in a tilted, precessing disk surrounding the white dwarf star. We present a preliminary orbital solution from radial velocity measurements of features from the accretion disk and the photosphere of the companion. We use a Doppler tomography algorithm to reconstruct the disk and companion spectra, and we also consider how these components contribute to the object's spectral energy distribution from ultraviolet to infrared wavelengths. This target offers us a remarkable opportunity to investigate disk processes during the high mass transfer stage of evolution in cataclysmic variables.Comment: 31 pages, 13 figures, accepted for Ap

Deposition And Drying Dynamics Of Liquid Crystal Droplets

Drop drying and deposition phenomena reveal a rich interplay of fundamental science and engineering, give rise to fascinating everyday effects (coffee rings), and influence technologies ranging from printing to genotyping. Here we investigate evaporation dynamics, morphology, and deposition patterns of drying lyotropic chromonic liquid crystal droplets. These drops differ from typical evaporating colloidal drops primarily due to their concentration-dependent isotropic, nematic, and columnar phases. Phase separation occurs during evaporation, and in the process creates surface tension gradients and significant density and viscosity variation within the droplet. As a result, the drying multiphase drops exhibit different convective currents, drop morphologies, and deposition patterns (coffee-rings)