Knowing We Don\u27t Know (Chapter One of When Faith Fails)

Excerpt: The first step into something new often looks like trust, not clarity. I began to discover the meaning of those words when I packed up everything I owned and moved from Oregon to the jungles of Vanuatu. Never heard of it? Neither had I when my pastor invited me to go. It will be great, he said. You\u27ll be teaching a group of college-aged students who come from all over the country to learn. Impulsive, in my early twenties, and evidently ready for adventure, I said yes, then hurried to the store to pick up a map. I spent forty-five minutes searching for Vanuatu. Assuming it was in Africa, my eyes scoured the continent. Finally, I realized Vanuatu is nowhere near Africa. It\u27s a group of eighty-two islands in the South Pacific, about 750 miles from Fiji. Still totally clueless, I said my goodbyes and got on a plane, about to begin one of the most exciting and unforgettable seasons of my life

The origin of the soft excess in high L/L_Edd AGN

We discuss the origin of the soft X-ray excess seen in AGN. There are clear advantages to models where this arises from atomic processes in partially ionised material rather than where it is a true continuum component. However, current data cannot distinguish between models where this material is seen in reflection or absorption, even for the archetypal 'reflection dominated' AGN MCG-6-30-15. Instead, we give physical arguments on the ionisation structure of X-ray illuminated material which exclude a reflection origin if the disc is in hydrostatic equilibrium. The same physical processes strongly favour an absorption origin for the soft excess, giving a more messy picture of the accretion environment. This implies that these apparently 'reflection dominated' AGN are not good places to test GR, but they do give insight into the spectra expected from the first QSO's in the early Universe.Comment: 4 pages, 2 figures, for the conference proceedings of "The Extreme Universe in the Suzaku Era",(Progress of Theoretical Physics, Supplement

Modelling the high mass accretion rate spectra of GX 339-4: Black hole spin from reflection?

We extract all the XMM-Newton EPIC pn burst mode spectra of GX 339-4, together with simultaneous/contemporaneous RXTE data. These include three disc dominated and two soft intermediate spectra, and the combination of broad bandpass/moderate spectral resolution gives some of the best data on these bright soft states in black hole binaries. The disc dominated spectra span a factor three in luminosity, and all show that the disc emission is broader than the simplest multicolour disc model. This is consistent with the expected relativistic smearing and changing colour temperature correction produced by atomic features in the newest disc models. However, these models do not match the data at the 5 per cent level as the predicted atomic features are not present in the data, perhaps indicating that irradiation is important even when the high energy tail is weak. Whatever the reason, this means that the data have smaller errors than the best physical disc models, forcing use of more phenomenological models for the disc emission. We use these for the soft intermediate state data, where previous analysis using a simple disc continuum found an extremely broad residual, identified as the red wing of the iron line from reflection around a highly spinning black hole. However, the iron line energy is close to where the disc and tail have equal fluxes, so using a broader disc continuum changes the residual 'iron line' profile dramatically. With a broader disc continuum model, the inferred line is formed outside of 30 ${\rm{R_g}}$, so cannot constrain black hole spin. We caution that a robust determination of black hole spin from the iron line profile is very difficult where the disc makes a significant contribution at the iron line energy i.e. in most bright black hole states.Comment: 12 pages, 16 figures, published in MNRA

Integrating supply chains: An investigation of collaborative knowledge transfers

This paper aims to empirically investigate the impact upon performance of explicit knowledge transfer in the integrated supply chain between a manufacturer and its external suppliers and customers. Literature derived hypotheses were evaluated using International Manufacturing Strategy Survey data from 338 companies. Valid and reliable scales were created via confirmatory factor analysis, and effects upon inventory performance tested via regression techniques. Whilst knowledge transfers from upstream and downstream directions were positively related to a manufacturer's performance, knowledge derived from customers was more powerful. Furthermore, integrated knowledge transfer- the combination of knowledge emanating from both suppliers and customers- had the strongest link to performance. The implications for practioners are that integrating knowledge across supply chains could be more far reaching than the exchange of assets, data and information usually considered in supply chain literature. Furthermore the current generalized approach to managing external knowledge is inadequate. This study expands upon existing literature by including directional implications as to which knowledge inflows are most valuable. For academics, this paper supports and extends existing literature by considering the supplier-manufacturer-customer triad in unison. The focus goes beyond asset, data and information exchange towards the leveraging of external knowledge. Relevant perspectives and dimensions were adopted from the knowledge management stream in order to add conceptual depth. Several areas of knowledge-based supply chain research have been identified as potential opportunities for further investigation.Supply Chain; Knowledge Management; Empirical Research:

Developing supply chain maturity

This study introduces an empirical model of supply chain maturity and assesses its impact upon performance. Findings suggest that supply chain maturity is multi-dimensional including the areas of planning, sourcing, making, delivering, new product development, and returning. Valid and reliable measures, scales and supply chain maturity constructs were formulated and significant positive links found with multiple objective performance measures. The supply chain maturity framework is thus concluded to be robust for answering questions relating to where a supply chain is in developmental terms and what may be done to continue improving upon the design. Possible areas for further research and implications for managers are also raised.Supply Chain Design; Supply Chain Coordination;

Supply chain knowledge management: A conceptual framework

The supply chain literature still largely focuses on asset, alphanumeric data and information (in the form of documents and files) elements of exchange between supply chain partners, despite the fact that increased integration and collaboration clearly require development of more complex elements of expertise and knowledge. In this respect, this paper recognizes the knowledge management (KM) literature as a potential source of new insights to add conceptual depth and understanding to managing 21st century supply chains. Specific KM theories and constructs are identified as potentially contributing to theory and practice in supply chain contexts. An overall framework for supply chain knowledge management is developed, along with literature-based definitions of supply chain knowledge transfer, competence and maturity constructs. The "knowledge lens" theory building approach is applied to import these perspectives into supply chain domains, with efforts to maintain conceptual consistency across the two literature streams.Knowledge Management; Supply Chains; Conceptual Framework;

Developing operational competence in purchasing

This paper contributes to the emerging theory of purchasing competence. First, it replicates and cross-validates the construct with five underlying supply-side competence dimensions of Narasimhan, Jayaram and Carter (2001), using telephone survey data from 200 high-turnover European companies. The addition of an IT Competence dimension to the construct is proposed and empirically validated. In response to the growing importance of services, equivalence of the competence construct across manufacturing and financial services contexts was shown using the structural equation technique of invariance analysis. Using set correlation analysis competence dimensions were found to be significant drivers of multiple operational performance measures. All competence dimensions had significant positive impact upon at least one performance measure. IT Competence had the most significant positive impact, driving Quality, Purchase-Order Cycle Time and Professionalism. Certain dimensions had significant negative effects upon performance, providing evidence for the possible existence of "competency trap" phenomena.Operational Competence; Purchasing; Empirical Methods;

The X-ray Binary Analogy to the First AGN QPO

The Narrow Line Seyfert 1 galaxy REJ1034+396 is so far unique amongst AGN in showing a Quasi-periodic oscillation (QPO) in its variability power spectrum. There are multiple types of QPO seen in black hole binary (BHB) systems, so we need to identify which BHB QPO corresponds to the one seen in the AGN. A key hint is the `hot disc dominated' energy spectrum of REJ1034+396 which is sufficiently unusual that it suggests a mildly super-Eddington flow, also favoured by the most recent mass estimates for the AGN. This suggests the 67Hz QPO seen occasionally in the mildly super-Eddington BHB GRS 1915+105 as the most likely counterpart, assuming mass scaling of the QPO frequency. This is supported by the fact that these data from GRS 1915+105 have an energy spectrum which is also dominated by a `hot disc' component. Here we show that the underlying broad band power spectral shape and normalisation are also similar, providing further consistency checks for this identification. Thus the AGN QPO adds to the growing evidence for a simple mass scaling of the accretion flow properties between stellar and supermassive black holes.Comment: 9 pages, 12 figures, to be published in MNRA