4,431 research outputs found

    Rebalancing the board's agenda

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    Since 2002, the activities of corporate boards have been dominated by the governance agenda. In Europe - to an even greater degree than the United States - governance codes have proliferated. This paper examines the resulting imbalance, where compliance with codes of conduct threatens to overwhelm the board's primary responsibility, i.e. the creation of wealth. We consider a model of board processes that starts with four key roles: setting direction, marshalling resources, controlling and reporting, and evaluating and enhancing for the next cycle. "We must urgently bring back some pragmatism to corporate governance . . . And if we want principles, not detailed rules that try to pre-empt all the eventualities a lawyer can think of." Peter Brabeck-Letmathe, CEO, Nestlé SA. The governance agenda has rightly drawn attention to the work of board committees and the question of the independence of mind directors need to show. But it may have diverted focus from three questions that ought to figure more prominently in the board's work: • How should the board apportion its work between compliance, risk assessment and setting strategic directions? • How do directors become determine when to focus on risk-mitigation and when to encourage strategic risk-taking? • In face of greater personal accountability for governance compliance, where do they draw the line between their role overseeing management and interfering with management's responsibilities? ABSTRACT FROM AUTHOR Copyright of Journal of General Management is the property of Braybrooke Press Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract

    Strong nonlinear optical response of graphene flakes measured by four-wave mixing

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    We present the first experimental investigation of nonlinear optical properties of graphene flakes. We find that at near infrared frequencies a graphene monolayer exhibits a remarkably high third-order optical nonlinearity which is practically independent of the wavelengths of incident light. The nonlinear optical response can be utilized for imaging purposes, with image contrasts of graphene which are orders of magnitude higher than those obtained using linear microscopy.Comment: 4 pages, 5 figure

    Controlling the generation of THz radiation from metallic films using periodic microstructure

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    We report on THz frequency generation via irradiation of microstructured semicontinuous silver films by femtosecond laser pulses. By patterning the film so as to produce an array of microstrips, we show that one can use periodic microstructure to control the way nanostructured metal films produce THz radiation when illuminated by femtosecond infrared laser pulses. A simple analytical model based on the field distribution arising from an array of THz dipole emitters is used to assess the experimental data, allowing us to explain some of the main features of the generated THz radiation patterns, including the strongly resonant features of the emission spectrum

    The development and sea trials of a subsea holographic camera for large volume in-situ recording of marine organisms

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    We describe the development, construction and sea testing of an underwater holographic camera (HoloCam) for in situ recording of marine organisms and particles in large volumes of sea water. HoloCam comprises a laser, power supply, holographic recording optics and plate holders, a water-tight housing and a support frame. Added to this are control electronics such that the entire camera is remotely operable and controllable from ship or dock-side. Uniquely the camera can simultaneously record both in-line and off-axis holograms using a pulsed frequency doubled Nd-YAG laser. In-line holography is capable of producing images of organisms with a resolution of better than 10 Pm (at concentrations up to a few thousand per cubic centimetre at the smallest sizes). Off-axis holograms of aquatic systems of up to 50,000 cm3 volume, have been recorded. Following initial laboratory testing, the holo-camera was evaluated in an observation tank and ultimately was tested in Loch Etive, Scotland. In-line and off-axis holograms were recorded to a depth of 100 m. We will present results on the test dives and evaluation of the camera performance

    The role of benthic biofilm production in the mediation of silicon cycling in the Severn Estuary, UK

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    The biological mediation of benthic biogenic silica (BBSi) by the diatom-dominated biofilms on the intertidal mudflats of the Severn Estuary (UK) was assessed in situ under different environmental conditions using measurements of productive biomass (chlorophyll a), photosynthetic activity of undisturbed microalgal assemblages, benthic biogenic silica (BBSi) and benthic dissolved silica (BDSi). We show low BBSi standing stocks in the mudflats compared to other European estuaries, under both warmer summer conditions (0.6%) and colder winter conditions (0.5%). Dissolved forms of Si (BDSi) dominated the estuary, with significantly higher concentrations during the sampled winter (22.6 ± 1.0 mg L−1) compared to the sampled summer (2.9 ± 0.5 mg L−1). Benthic algal biomass was higher under cold conditions compared to warmer conditions (24.0 ± 2.3 and 13.2 ± 1.9 mg g−1sed. dw., respectively), following reduced migratory behaviour in the winter increasing surficial biomass. Relative maximum Electron Transport Rate (rETRmax), used as a proxy for relative primary productivity, was higher under warm conditions (254.1 ± 20.1 rel. units) compared to cold conditions (116.0 ± 27.1 rel. units). The biofilms sampled in the summer biologically mediated Si by the productive, high light acclimated diatoms that were highly motile during fluorescence measurements, and exhibited migratory behaviour, which despite nutrient limitation, evidenced by low Fv/Fm, increased the accumulation of BBSi. The biofilms sampled in the winter that were subject to relatively colder temperatures, consisted of low light acclimated diatoms of reduced migratory capabilities, and induced NPQ that suppressed productivity, and mediated BBSi to a lesser extent. Environmental stresses reduced the biofilm biological mediation of Si, which controlled Si to a lesser extent compared to the high hydrodynamic energy increasing biofilm re-suspension and terrestrial/coastal inputs

    Developing principles of best practice for art therapists working with children and families

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    In 2010 the British Association of Art therapists asked art therapists working with specific client groups to produce clear guidelines about current views on best practice in the field. Using the Nominal Group Technique and a modified Delphi process, the special interest group Art Therapists working with Children Adolescents and Families (ATCAF) produced 18 Principles of Best Practice with a range of associated indicators. This paper presents the methods and the results of that process followed by a brief discussio

    Role of Dielectric Drag in Polaron Mobility in Lead Halide Perovskites

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    This is the author accepted manuscript. The final version is available from American Chemical Society via the DOI in this record.Hybrid organic-inorganic lead halide perovskites (HOIPs) have attracted much attention because of their remarkable carrier lifetimes and diffusion lengths. These properties have been attributed to the efficient screening of charge carriers via polaron formation in the highly polar and dynamic environment. Polaron formation explains, at least in part, the moderate charge carrier mobility, but the calculated mobilities are somewhat higher than experimental values. Here we discuss a factor that has been previously overlooked and can potentially account for the discrapency: the effect of dielectric drag. While optical phonon modes of the lead halide sublattice are mainly responsible for polaron formation, slower orientational relaxation of surrounding dipoles adds a dielectric drag to the moving charge. We discuss the role of this dielectric drag based on the measured dielectric function in the gigahertz to terahertz frequency range and how we can understand the unique carrier physics in HOIPs in view of its crystal-liquid duality.We thank Prof. X. Roy, Dr. Johannes Hunger, Dr. Jarvist Frost, Prof. Shaul Mukamel, Prof. Casey Hynes, and Prof. Louis Brus for insightful discussions. X.Y.Z. thanks Profs. Song Jin, Vitaly Podzorov, and Filippo De Angelis for fruitful collaborations and his group, particularly Dr. Daniel Niesner, Dr. Xiaoxi Wu, Dr. Haiming Zhu, Dr. M. Tuan Trinh, Mr. Jue Wang, and Ms. Prakriti Joshi, for the experimental work which precipitated the ideas presented here. X.Y.Z. acknowledges U.S. Department of Energy, Office of Science - Basic Energy Sciences, Grant ER46980 for support during the writing of this Perspective. K.M. acknowledges JSPS for financial support

    HoloCam: A subsea holographic camera for recording marine organisms and particles

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    The HoloCam system is a major component of a multi-national multi-discipline project known as HoloMar (funded by the European Commission under the MAST III initiative). The project is concerned with the development of pulsed laser holography to analyse and monitor the populations of living organisms and inanimate particles within the world's oceans. We describe here the development, construction and evaluation of a prototype underwater camera, the purpose of which is to record marine organisms and particles, in-situ. Recording using holography provides several advantages over conventional sampling methods in that it allows non-intrusive, non-destructive, high-resolution imaging of large volumes (up to 10^5 cm^3) in three dimensions. The camera incorporates both in-line and off-axis holographic techniques, which allows particles from a few micrometres to tens of centimetres to be captured. In tandem with development of the HoloCam, a dedicated holographic replay system and an automated data extraction and image processing facility are being developed. These will allow, optimisation of the images recorded by the camera, identification of species and particle concentration plotting
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