151 research outputs found

    Optical carrier wave shocking: detection and dispersion

    Full text link
    Carrier wave shocking is studied using the Pseudo-Spectral Spatial Domain (PSSD) technique. We describe the shock detection diagnostics necessary for this numerical study, and verify them against theoretical shocking predictions for the dispersionless case. These predictions show Carrier Envelope Phase (CEP) and pulse bandwidth sensitivity in the single-cycle regime. The flexible dispersion management offered by PSSD enables us to independently control the linear and nonlinear dispersion. Customized dispersion profiles allow us to analyze the development of both carrier self-steepening and shocks. The results exhibit a marked asymmetry between normal and anomalous dispersion, both in the limits of the shocking regime and in the (near) shocked pulse waveforms. Combining these insights, we offer some suggestions on how carrier shocking (or at least extreme self-steepening) might be realised experimentally.Comment: 9 page

    Uncomfortable truths - teamworking under lean in the UK

    Get PDF
    A recent contribution in this journal – Procter, S. and Radnor, Z. (2014) ‘Teamworking under Lean in UK public services: lean teams and team targets in Her Majesty’s Revenue and Customs (HMRC)’ International Journal of Human Resource Management, 25:21, 2978–2995 – provides an account of teamworking in the UK Civil Service, specifically Her Majesty’s Revenue and Customs (HMRC), focused on the relationship between recently implemented lean work organisation and teams and teamworking. Procter and Radnor claim in this work that it delivers a ‘more nuanced’ analysis of lean in this government department and, it follows, of the lean phenomenon more generally. Our riposte critiques their article on several grounds. It suffers from problems of logic and construction, conceptual confusion and definitional imprecision. Methodological difficulties and inconsistent evidence contribute additionally to analytical weakness. Included in our response are empirical findings on teamworking at HMRC that challenge Procter and Radnor’s evidential basis and further reveal the shortcomings of their interpretation

    Carrier-wave steepened pulses and gradient-gated high-order harmonic generation using linear ramp waveforms

    Full text link
    We show how to optimize the process of high-harmonic generation (HHG) by gating the interaction using the field gradient of a driving pulse with a linear ramp waveform. Since maximized field gradients are efficiently generated by self-steepening processes, we first present a generalized theory of optical carrier-wave self-steepened (CSS) pulses. This goes beyond existing treatments, which only consider third-order nonlinearity, and has the advantage of describing pulses whose wave forms have a range of symmetry properties. Although a fertile field for theoretical work, CSS pulses are difficult to realize experimentally because of the deleterious effect of dispersion. We therefore consider synthesizing CSS-like profiles using a suitably phased sub-set of the harmonics present in a true CSS wave form. Using standard theoretical models of HHG, we show that the presence of gradient-maximized regions on the wave forms can raise the spectral cut-off and so yield shorter attosecond pulses. We study how the quality of the attosecond bursts created by spectral filtering depends on the number of harmonics included in the driving pulse.Comment: 8 pages, 10 figures; with appendix not present in published versio

    On publicness theory and its implications for supply chain integration:The case of criminal justice supply chains

    Get PDF
    The literature has extensively discussed whether and how public organizations differ from private ones. Publicness theory argues that the degree of publicness is determined by ownership, funding, goal setting, and control structure of an organization. However, these theoretical ideas have not yet been extended to the interorganizational level. The need for further research is reflected in the sustained debate on the applicability of for-profit management approaches in public contexts and supply chains. Starting from the premise of the dimensional publicness theory, this study focuses on theory elaboration. We focus our empirical study on the criminal justice supply chain, which encompasses the process of bringing a criminal case to court. This chain provides an interesting public case to explore how specific dimensions of publicness affect or limit supply chain integration mechanisms. The results of our series of embedded cases focusing on Dutch criminal justice supply chains show that control structures, embodied in laws and regulations, define the governance of relationships between supply chain partners. In addition to these formalized ties, extensive known for-profit information and operational integration mechanisms can be observed, along with limited relational integration. Surprisingly, although similar integration mechanisms are used as in for-profit contexts, integration serves a different role in several of the relationships investigated: dealing with tensions stemming from the specific goal setting and stakeholders of criminal justice chains. Although our findings specifically relate to criminal justice supply chains, they have important implications for other supply chains using contracts and laws and those being selective in applying supply chain integration in cases of contrasting objectives. Moreover, we provide a stepping-stone for the extension of publicness theory to the interorganizational level
    corecore