The Expanding Fireball of Nova Delphini 2013

A classical nova occurs when material accreting onto the surface of a white dwarf in a close binary system ignites in a thermonuclear runaway. Complex structures observed in the ejecta at late stages could result from interactions with the companion during the common envelope phase. Alternatively, the explosion could be intrinsically bipolar, resulting from a localized ignition on the surface of the white dwarf or as a consequence of rotational distortion. Studying the structure of novae during the earliest phases is challenging because of the high spatial resolution needed to measure their small sizes. Here we report near-infrared interferometric measurements of the angular size of Nova Delphini 2013, starting from one day after the explosion and continuing with extensive time coverage during the first 43 days. Changes in the apparent expansion rate can be explained by an explosion model consisting of an optically thick core surrounded by a diffuse envelope. The optical depth of the ejected material changes as it expands. We detect an ellipticity in the light distribution, suggesting a prolate or bipolar structure that develops as early as the second day. Combining the angular expansion rate with radial velocity measurements, we derive a geometric distance to the nova of 4.54 +/- 0.59 kpc from the Sun.Comment: Published in Nature. 32 pages. Final version available at http://www.nature.com/nature/journal/v515/n7526/full/nature13834.htm

Agency, stewardship and the universal-family firm : a qualitative historical analysis

This paper introduces the idea of a non-kinship-based Universal-family firm, an organizational form we developed based on interpreting historical writings in their socio-economic context. We analyzed Luke’s gospel with an eye toward drawing implications for the stewardship-agency debate in the contemporary family business literature. Our paper makes contributions at two important levels. In addition to introducing and developing theory about the Universal-family firms, we also contribute to the methodological toolkit of family business scholars by providing a template for using historical documents to challenge, enhance and develop theory

The 2014 interferometric imaging beauty contest

This is the final version of the article. Available from SPIE via the DOI in this record.From Conference Volume 9146: Optical and Infrared Interferometry IV. Jayadev K. Rajagopal; Michelle J. Creech-Eakman; Fabien Malbet. Montréal, Quebec, Canada, June 22, 2014Here we present the results of the 6th biennial optical interferometry imaging beauty contest. Taking advantage of a unique opportunity, the red supergiant VY CMa and the Mira variable R Car were observed in the astronomical H-band with three 4-telescope configurations of the VLTI-AT array using the PIONIER instrument. The community was invited to participate in the subsequent image reconstruction and interpretation phases of the project. Ten groups submitted entries to the beauty contest, and we found reasonable consistency between images obtained from independent workers using quite different algorithms. We also found that significant differences existed between the submitted images, much greater than in past beauty contests that were all based on simulated data. A novel crowd-sourcing" method allowed consensus median images to be constructed, filtering likely artifacts and retaining real features." We definitively detect strong spots on the surfaces of both stars as well as distinct circumstellar shells of emission (likely water/CO) around R Car. In a close contest, Joel Sanchez (IAA-CSIC/Spain) was named the winner of the 2014 interferometric imaging beauty contest. This process has shown that new comers" can use publicly-available imaging software to interpret VLTI/PIONIER imaging data, as long as sufficient observations are taken to have complete uv coverage { a luxury that is often missing. We urge proposers to request adequate observing nights to collect sufficient data for imaging and for time allocation committees to recognise the importance of uv coverage for reliable interpretation of interferometric data. We believe that the result of the proposed broad international project will contribute to inspiring trust in the image reconstruction processes in optical interferometry

The expanding fireball of Nova Delphini 2013

A classical nova occurs when material accreting onto the surface of a white dwarf in a close binary system ignites in a thermonuclear runaway. Complex structures observed in the ejecta at late stages could result from interactions with the companion during the common-envelope phase. Alternatively, the explosion could be intrinsically bipolar, resulting from a localized ignition on the surface of the white dwarf or as a consequence of rotational distortion. Studying the structure of novae during the earliest phases is challenging because of the high spatial resolution needed to measure their small sizes. Here we report near-infrared interferometric measurements of the angular size of Nova Delphini 2013, starting one day after the explosion and continuing with extensive time coverage during the first 43 days. Changes in the apparent expansion rate can be explained by an explosion model consisting of an optically thick core surrounded by a diffuse envelope. The optical depth of the ejected material changes as it expands. We detect an ellipticity in the light distribution, suggesting a prolate or bipolar structure that develops as early as the second day. Combining the angular expansion rate with radial velocity measurements, we derive a geometric distance to the nova of 4.54 ± 0.59 kiloparsecs from the Sun.This material is based upon work supported by the National Science Foundation under grant number AST-1009080. The CHARA Array is funded by the National Science Foundation through NSF grants AST 0908253 and AST 1211129, and by Georgia State University through the College of Arts and Sciences

Online Stakeholder Interactions in the Early Stage of a Megaproject

The purpose of this paper is to examine the network structure of online stakeholder discussions in the planning stage of a UK public mega project, High Speed Rail. By providing new rail connections between London, Birmingham and Manchester, this project is highly complex as it is embedded in a network of stakeholder relationships that may support or oppose the project. Data drawn from Twitter was analyzed using Social Network Analysis and inductive analysis of user profiles and content. Findings indicate that the majority of online stakeholders oppose the project and form stable clusters. Larger clusters within this network may attempt to deploy power directly in the form of a manipulation strategy while smaller clusters may seek to ally themselves with more powerful groups, a pathway strategy. Overall, the methodology is a useful complement to existing methods and may provide real time insights into the complex, evolving discussions around mega projects

Systematic review of epidemiological studies on health effects associated with management of solid waste

Background: Management of solid waste (mainly landfills and incineration) releases a number of toxic substances, most in small quantities and at extremely low levels. Because of the wide range of pollutants, the different pathways of exposure, long-term low-level exposure, and the potential for synergism among the pollutants, concerns remain about potential health effects but there are many uncertainties involved in the assessment. Our aim was to systematically review the available epidemiological literature on the health effects in the vicinity of landfills and incinerators and among workers at waste processing plants to derive usable excess risk estimates for health impact assessment.Methods: We examined the published, peer-reviewed literature addressing health effects of waste management between 1983 and 2008. For each paper, we examined the study design and assessed potential biases in the effect estimates. We evaluated the overall evidence and graded the associated uncertainties.Results: In most cases the overall evidence was inadequate to establish a relationship between a specific waste process and health effects; the evidence from occupational studies was not sufficient to make an overall assessment. For community studies, at least for some processes, there was limited evidence of a causal relationship and a few studies were selected for a quantitative evaluation. In particular, for populations living within two kilometres of landfills there was limited evidence of congenital anomalies and low birth weight with excess risk of 2 percent and 6 percent, respectively. The excess risk tended to be higher when sites dealing with toxic wastes were considered. For populations living within three kilometres of old incinerators, there was limited evidence of an increased risk of cancer, with an estimated excess risk of 3.5 percent. The confidence in the evaluation and in the estimated excess risk tended to be higher for specific cancer forms such as non-Hodgkin's lymphoma and soft tissue sarcoma than for other cancers.Conclusions: The studies we have reviewed suffer from many limitations due to poor exposure assessment, ecological level of analysis, and lack of information on relevant confounders. With a moderate level confidence, however, we have derived some effect estimates that could be used for health impact assessment of old landfill and incineration plants. The uncertainties surrounding these numbers should be considered carefully when health effects are estimated. It is clear that future research into the health risks of waste management needs to overcome current limitations