Lobe Overflow as the Likely Cause of Pericenter Outburst in an SMBH Orbiter

A very large lobe overflow event is suggested to explain the $0.^m4$ brightening observed in K band at pericenter passage of the star known as S2 that orbits the Galaxy's supermassive black hole (SMBH). Known observed properties of S2 that contribute to lobe filling are 1) the enormous mass ratio, $M_{SMBH}/M_{S2}$, 2) S2's fast rotation, and 3) S2's large orbital eccentricity. Published estimates have given limiting lobe sizes of order 100 to 300 $R_\odot$ but, with S2's fast rotation taken into account, the computed lobe size is much smaller, being compatible with either a main sequence OB star or a stripped evolved star. An important evolutionary consideration that predicts very large pericenter overflows is envelope expansion following mass loss that is characteristic of highly evolved stars. Material removed by lobe overflow at pericenter is replenished by envelope expansion as an evolved star awaits its next pericenter passage. An observational signature of lobe overflow for upcoming pericenter passages would be appearance of emission lines as the ejected gas expands and becomes optically thin.Comment: Accepted by ApJ April 201

Artificial Intelligence Approach to the Determination of Physical Properties of Eclipsing Binaries. I. The EBAI Project

Achieving maximum scientific results from the overwhelming volume of astronomical data to be acquired over the next few decades will demand novel, fully automatic methods of data analysis. Artificial intelligence approaches hold great promise in contributing to this goal. Here we apply neural network learning technology to the specific domain of eclipsing binary (EB) stars, of which only some hundreds have been rigorously analyzed, but whose numbers will reach millions in a decade. Well-analyzed EBs are a prime source of astrophysical information whose growth rate is at present limited by the need for human interaction with each EB data-set, principally in determining a starting solution for subsequent rigorous analysis. We describe the artificial neural network (ANN) approach which is able to surmount this human bottleneck and permit EB-based astrophysical information to keep pace with future data rates. The ANN, following training on a sample of 33,235 model light curves, outputs a set of approximate model parameters (T2/T1, (R1+R2)/a, e sin(omega), e cos(omega), and sin i) for each input light curve data-set. The whole sample is processed in just a few seconds on a single 2GHz CPU. The obtained parameters can then be readily passed to sophisticated modeling engines. We also describe a novel method polyfit for pre-processing observational light curves before inputting their data to the ANN and present the results and analysis of testing the approach on synthetic data and on real data including fifty binaries from the Catalog and Atlas of Eclipsing Binaries (CALEB) database and 2580 light curves from OGLE survey data. [abridged]Comment: 52 pages, accepted to Ap

Modular strategies: B2B technology and architectural knowledge

Business-to-business information technology systems are becoming increasingly important in firm supply chains. Utilizing the concept of modularity, this article clarifies the strategic implications of B2B technology. There are two generic B2B strategies: modularization, which allows a firm to rent out its internal capabilities to others in its industry; and architectural entrepreneurship, which alters the supply chain by allowing a central coordinating firm to facilitate arrangements that trust issues and information asymmetries had previously made impossible. Which modular strategy is appropriate depends on the role the focal firm plays in the supply chain and their supply chain indispensability. Only firms with deep architectural knowledge can take full advantage of these modular strategies

A model for the X-ray nova A0620-00

The model involves a white dwarf accreting mass from a late-type subgiant companion. The transient behavior of the X-ray source is explained by the instability to mass loss of the companion (as in Algol-type binaries). The brightening, spectrum, and decay timescale of the optical counterpart are explained in terms of re-emission of X-radiation intercepted by the subgiant. It was concluded that A0620-00 can provide an excellent test case for numerical models of stellar atmospheres irradiated by an external X-ray flux

Influence and power dynamics in client-consultant teams

© 2009, © Emerald Group Publishing Limited. Purpose – The aim of this paper is to provide a clearer picture of the nature of power imbalance in client-consultant teams, which has negative consequences for the development and implementation of consultants' recommendations, and to outline ways how to avoid such an imbalance in the first instance. Design/methodology/approach – This is an empirical paper based on in-depth semi-structured interviews with clients and consultants from the strategic consulting sector in Australia. Findings – Taking a differentiated look at the roles and responsibilities of members of client-consultant teams, the authors propose that power within client-consultant teams is multidimensional and the outcome of the interplay of its different forms is not predictable. It is further argued that a power balance is crucial for achieving better results from consulting projects. Research limitations/implications – The findings are not generalizable, due to the small sample and the focus on strategic consulting. The results encourage further research in different types of consulting projects as well as studies based on observation of client-consultant interactions. Practical implications – The paper highlights the main points of concern for managers and consultants and provides some suggestions on how to achieve a balanced relationship. Originality/value – This paper's major contribution is in providing deeper insight into a hitherto underexplored issue of client-consultant interactions: the contested nature of power in client-consultant teams and the reasons and outcomes of power imbalance

Building community

That organizations cannot be viewed as uniform and stable cultures or entities but rather as communities of “loosely constituted overlapping circles of partialled participation” (Blau, 1996: 174) is not a new insight (e.g., Bechky, 2003; Bloor and Dawson, 1994; Dougherty, 1992). To make sense of this world of competing communities, one needs to understand why these subcultures exist, how they form, how they interact—cooperatively and competitively—and how they evolve. In what follows, we address these issues by providing an integrated view of the two theoretical approaches that have built on this thinking: communities of prac-tice (CoP) and critical discourse analysis (CDA). The concept of interpretive communities (ICs), which we propose, builds upon important findings related to both CoP and CDA but overcomes their shortcomings and extends them onto a more general theoretical footing

Knowledge management: Philosophy, process, and pitfalls

According to a leading scholar of management James Brian Quinn,' "The capacity to manage human intellectand to transform intellectual output into a service or a group of services embodied in a product is fast becoming the critical executive skill of this era." Contrast that with the assertion by the pointy-haired boss of the Dilbert cartoon that his company's success will be driven by "redesigning processes to enable enterprise integration of knowledge resources and tools." The first is a serious, thoughtful, and eminently reasonable statement of a belief in the transformation of management. The second is a caricature of that belief, subsequently doused by Wally's response, "Is it okay if I do nothing?" Leave it to Scott Adams and his alter egos to gut the sanctity from the latest management fad

What Matters to Australians: Our Social, Political and Economic Values

Societies are complex entities with competing and conflicting and supporting and reinforcing characteristics. This study, part of a multiyear project sponsored by the Australian Research Council (ARC) in conjunction with the University of Technology, Sydney and Melbourne Business School, seeks to chart the social, economic and political preferences of our society using a unique methodology that provides us with a more accurate and robust picture of how we, as citizens, make fundamental trade-offs about things of material interest to our society. The study was conducted in Australia with more than 1,500 participants chosen to match the profile of the voting age population. Similar studies were conducted in the UK, USA and Germany. Examined were 16 categories of general social, economic and political issues that ranged from the local (e.g., crime & public safety) to the global (e.g., global security) along with 113 subissues that also varied from the local (e.g., public transport and children’s schooling) to the global (e.g., nuclear non-proliferation and third world debt). This information was linked to information on the population’s religious and political activities, its general demographics, and donating and volunteering activities with civil society organisations

The role of fairness and ambiguity in negotiating marketing alliances

This paper provides empirical support for the positive effects of distributive, procedural and interactional fairness on the choice to form a marketing alliance. Furthermore, the results provide some support for the negative impact of ambiguity in respect to the partner’s marketing capabilities on the choice to form a marketing alliance

What Matters to Americans: Social, Political and Economic Values

Societies are complex entities with competing and conflicting and supporting and reinforcing characteristics. This study, part of a multiyear project sponsored by the Australian Research Council (ARC) in conjunction with the University of Technology, Sydney and Melbourne Business School, seeks to chart the social, economic and political preferences of society, using a unique methodology that provides us with a more accurate and robust picture of how individuals, as citizens, make fundamental trade-offs about things of material interest to their society. The study was conducted in the United States of America with more than 2,800 participants, chosen to match the profile of the voting age population. Similar studies were conducted in the UK, Australia and Germany, providing data on more than 9,000 individuals.1 Examined were 16 categories of general social, economic and political issues that ranged from the local (for example, crime and public safety) to the global (for example, global security) along with 113 sub-issues that also varied from the local (for example, public transport and children’s schooling) to the global (for example, nuclear nonproliferation and third world debt). This information was linked to data on the population’s religious and political activities, its general demographics, and donating and volunteering activities with civil society organizations