1,058 research outputs found

    Connecting up strategy: are senior strategy directors a missing link?

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    With companies being exhorted to become more strategically agile and internally connected, this article examines the role of the Senior Strategy Director, the executive tasked specifically with internal strategy. In particular, it explores what they do, what specific capabilities they deploy to enable effective contribution to the company, and in what ways they facilitate the connectedness of strategy. An analysis of multiple interviews over time with Senior Strategy Directors of large companies shows the vital and challenging role these executives play in both shaping, connecting up, and executing strategy. This article identifies the particular capabilities necessary for Senior Strategy Directors to perform their role and shows how it all depends upon their skilful deployment. These findings have significant implications for understanding unfolding micro-processes of strategy in large organizations, for assumptions about the skills and capabilities necessary to be an effective Senior Strategy Director, and for business schools in terms of the content and style of strategy courses they provide

    Black carbon aerosols and the third polar ice cap

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    Recent thinning of glaciers over the Himalayas (sometimes referred to as the third polar region) have raised concern on future water supplies since these glaciers supply water to large river systems that support millions of people inhabiting the surrounding 5 areas. Black carbon (BC) aerosols, released from incomplete combustion, have been increasingly implicated as causing large changes in the hydrology and radiative forcing over Asia and its deposition on snow is thought to increase snow melt. In India BC from biofuel combustion is highly prevalent and compared to other regions, BC aerosol amounts are high. Here, we quantify the impact of BC aerosols on snow cover and pre10 cipitation from 1990 to 2010 over the Indian subcontinental region using two different BC emission inventories. New estimates indicate that Indian BC from coal and biofuel are large and transport is expected to expand rapidly in coming years. We show that over the Himalayas, from 1990 to 2000, simulated snow/ice cover decreases by ~0.9% due to aerosols. The contribution of the enhanced Indian BC to this decline is ~30%, 15 similar to that simulated for 2000 to 2010. Spatial patterns of modeled changes in snow cover and precipitation are similar to observations (from 1990 to 2000), and are mainly obtained with the newer BC estimates

    Defect Engineering: Graphene Gets Designer Defects

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    An extended one-dimensional defect that has the potential to act as a conducting wire has been embedded in another perfect graphene sheet.Comment: 2 pages, 1 figur

    Resonant transmission through finite-sized carbon nanotubes

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    We have investigated theoretically the conductance through finite-sized carbon nanotubes coupled to featureless leads in the context of standard tight-binding models. Conduction takes place via resonant tunneling, and the resultant spectrum of peaks may be understood in terms of the band structure of the nanotubes. Specific nanotubes display both on- and off-resonance behavior as a function of nanotube length depending upon whether or not the bands cross at a nonzero k value. We have also investigated the approach to the infinite limit in detail, and, in general, find that the finite-size effects can persist out to hundreds of nanometers. Since the manipulation of nanotubes into devices is likely to induce defects, we have investigated their effects on the conduction. The effects of bending and two broad classes of defects, i.e., defect in the absence and/or presence of addimers, were considered. In general, the presence of defects leads both to a reduction and shifting of the resonant peaks at the Fermi level. However, in the infinite limit, low concentrations of defects have only a relatively modest effect on the transport properties. Finally, we have investigated the effects of an externally imposed magnetic field oriented perpendicular to the nanotube axis. The magnetic field shifts the levels, thereby turning on- and off-resonant devices into each other. All of the effects discussed here are testable experimentally.published_or_final_versio

    Towards a Conceptualization of Sociomaterial Entanglement

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    In knowledge representation, socio-technical systems can be modeled as multiagent systems in which the local knowledge of each individual agent can be seen as a context. In this paper we propose formal ontologies as a means to describe the assumptions driving the construction of contexts as local theories and to enable interoperability among them. In particular, we present two alternative conceptualizations of the notion of sociomateriality (and entanglement), which is central in the recent debates on socio-technical systems in the social sciences, namely critical and agential realism. We thus start by providing a model of entanglement according to the critical realist view, representing it as a property of objects that are essentially dependent on different modules of an already given ontology. We refine then our treatment by proposing a taxonomy of sociomaterial entanglements that distinguishes between ontological and epistemological entanglement. In the final section, we discuss the second perspective, which is more challenging form the point of view of knowledge representation, and we show that the very distinction of information into modules can be at least in principle built out of the assumption of an entangled reality

    Interference effects in electronic transport through metallic single-wall carbon nanotubes

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    In a recent paper Liang {\it et al.} [Nature {\bf 411}, 665 (2001)] showed experimentally, that metallic nanotubes, strongly coupled to external electrodes, may act as coherent molecular waveguides for electronic transport. The experimental results were supported by theoretical analysis based on the scattering matrix approach. In this paper we analyze theoretically this problem using a real-space approach, which makes it possible to control quality of interface contacts. Electronic structure of the nanotube is taken into account within the tight-binding model. External electrodes and the central part (sample) are assumed to be made of carbon nanotubes, while the contacts between electrodes and the sample are modeled by appropriate on-site (diagonal) and hopping (off-diagonal) parameters. Conductance is calculated by the Green function technique combined with the Landauer formalism. In the plots displaying conductance {\it vs.} bias and gate voltages, we have found typical diamond structure patterns, similar to those observed experimentally. In certain cases, however, we have found new features in the patterns, like a double-diamond sub-structure.Comment: 15 pages, 4 figures. To apear in Phys. Rev.
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