90 research outputs found

    Management by Textbook: The Role of Textbooks in Developing Critical Thinking

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    Ā© 2015, Ā© The Author(s) 2015. Critical thinking is widely regarded as a crucial capability for competent management and also for any leadership role in society. In this article, we ask, ā€œHow do textbooks play a role in the weakness of many management graduatesā€™ critical thinking skills?ā€ Management teachers can find plentiful advice about best teaching practices, yet the critical skills gap remains. We argue that the nature and use of management textbooks intersect and interact with studentsā€™ epistemology to support a culture of surface learning, resulting in a failure to develop critical thinking skills. Textbooks reinforce underdeveloped student epistemology through limitations of content and position students as passive recipients of an authoritative version of oversimplified knowledge. In our survey of 30 successful management textbooks, we found the majority of popular management textbooks potentially inhibit, or only weakly support, the development of studentsā€™ capacity for critical thinking. The article concludes with suggestions for improving textbooks and textbook choice or considering alternatives

    The strategic implications of sustainability in strategy textbooks

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    Underlying every strategic management textbook are numerous assumptions about the nature of the economic system, society and the environment. One assumption that seems saliently absent from management textbooks is sustainability. In view of the detailed critique of the design of the MBA set out in Bubna-Litic and Benn (2003) it is likely that a systematic study of strategy textbooks will reveal other similar omissions. This study analyses a number of strategy textbooks exploring how they engage with questions of sustainability. The findings show that although the increase in the ethical self-consciousness of environmental economics is visible, so too is a narrow view of sustainability

    Testbeam and Laboratory Characterization of CMS 3D Pixel Sensors

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    The pixel detector is the innermost tracking device in CMS, reconstructing interaction vertices and charged particle trajectories. The sensors located in the innermost layers of the pixel detector must be upgraded for the ten-fold increase in luminosity expected with the High- Luminosity LHC (HL-LHC) phase. As a possible replacement for planar sensors, 3D silicon technology is under consideration due to its good performance after high radiation fluence. In this paper, we report on pre- and post- irradiation measurements for CMS 3D pixel sensors with different electrode configurations. The effects of irradiation on electrical properties, charge collection efficiency, and position resolution of 3D sensors are discussed. Measurements of various test structures for monitoring the fabrication process and studying the bulk and surface properties, such as MOS capacitors, planar and gate-controlled diodes are also presented.Comment: 14 page

    Laboratory and testbeam results for thin and epitaxial planar sensors for HL-LHC

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    The High-Luminosity LHC (HL-LHC) upgrade of the CMS pixel detector will require the development of novel pixel sensors which can withstand the increase in instantaneous luminosity to L = 5 Ɨ 1034 cmā€“2sā€“1 and collect ~ 3000fbā€“1 of data. The innermost layer of the pixel detector will be exposed to doses of about 1016 neq/ cm2. Hence, new pixel sensors with improved radiation hardness need to be investigated. A variety of silicon materials (Float-zone, Magnetic Czochralski and Epitaxially grown silicon), with thicknesses from 50 Ī¼m to 320 Ī¼m in p-type and n-type substrates have been fabricated using single-sided processing. The effect of reducing the sensor active thickness to improve radiation hardness by using various techniques (deep diffusion, wafer thinning, or growing epitaxial silicon on a handle wafer) has been studied. Furthermore, the results for electrical characterization, charge collection efficiency, and position resolution of various n-on-p pixel sensors with different substrates and different pixel geometries (different bias dot gaps and pixel implant sizes) will be presented

    Test beam performance measurements for the Phase I upgrade of the CMS pixel detector

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    A new pixel detector for the CMS experiment was built in order to cope with the instantaneous luminosities anticipated for the Phase I Upgrade of the LHC. The new CMS pixel detector provides four-hit tracking with a reduced material budget as well as new cooling and powering schemes. A new front-end readout chip mitigates buffering and bandwidth limitations, and allows operation at low comparator thresholds. In this paper, comprehensive test beam studies are presented, which have been conducted to verify the design and to quantify the performance of the new detector assemblies in terms of tracking efficiency and spatial resolution. Under optimal conditions, the tracking efficiency is (99.95 Ā± 0.05) %, while the intrinsic spatial resolutions are (4.80 Ā± 0.25) Ī¼m and (7.99 Ā± 0.21) Ī¼m along the 100 Ī¼m and 150 Ī¼m pixel pitch, respectively. The findings are compared to a detailed Monte Carlo simulation of the pixel detector and good agreement is found.Peer reviewe

    Trapping in irradiated p-on-n silicon sensors at fluences anticipated at the HL-LHC outer tracker

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    The degradation of signal in silicon sensors is studied under conditions expected at the CERN High-Luminosity LHC. 200 Ī¼\mum thick n-type silicon sensors are irradiated with protons of different energies to fluences of up to 3ā‹…10153 \cdot 10^{15} neq/cm2^2. Pulsed red laser light with a wavelength of 672 nm is used to generate electron-hole pairs in the sensors. The induced signals are used to determine the charge collection efficiencies separately for electrons and holes drifting through the sensor. The effective trapping rates are extracted by comparing the results to simulation. The electric field is simulated using Synopsys device simulation assuming two effective defects. The generation and drift of charge carriers are simulated in an independent simulation based on PixelAV. The effective trapping rates are determined from the measured charge collection efficiencies and the simulated and measured time-resolved current pulses are compared. The effective trapping rates determined for both electrons and holes are about 50% smaller than those obtained using standard extrapolations of studies at low fluences and suggests an improved tracker performance over initial expectations

    Characterisation of irradiated thin silicon sensors for the CMS phase II pixel upgrade

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    The high luminosity upgrade of the Large Hadron Collider, foreseen for 2026, necessitates the replacement of the CMS experiment's silicon tracker. The innermost layer of the new pixel detector will be exposed to severe radiation, corresponding to a 1 MeV neutron equivalent fluence of up to Phi(eq) = 2x10(16) cm(-2), and an ionising dose of approximate to 5 MGy after an integrated luminosity of 3000 fb(-1). Thin, planar silicon sensors are good candidates for this application, since the degradation of the signal produced by traversing particles is less severe than for thicker devices. In this paper, the results obtained from the characterisation of 100 and 200 mu m thick p-bulk pad diodes and strip sensors irradiated up to fluences of Phi(eq) = 1.3 x 10(16) cm(-2) are shown.Peer reviewe

    Description and performance of track and primary-vertex reconstruction with the CMS tracker

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    A description is provided of the software algorithms developed for the CMS tracker both for reconstructing charged-particle trajectories in proton-proton interactions and for using the resulting tracks to estimate the positions of the LHC luminous region and individual primary-interaction vertices. Despite the very hostile environment at the LHC, the performance obtained with these algorithms is found to be excellent. For tbar t events under typical 2011 pileup conditions, the average track-reconstruction efficiency for promptly-produced charged particles with transverse momenta of pT > 0.9GeV is 94% for pseudorapidities of |Ī·| < 0.9 and 85% for 0.9 < |Ī·| < 2.5. The inefficiency is caused mainly by hadrons that undergo nuclear interactions in the tracker material. For isolated muons, the corresponding efficiencies are essentially 100%. For isolated muons of pT = 100GeV emitted at |Ī·| < 1.4, the resolutions are approximately 2.8% in pT, and respectively, 10Ī¼m and 30Ī¼m in the transverse and longitudinal impact parameters. The position resolution achieved for reconstructed primary vertices that correspond to interesting pp collisions is 10ā€“12Ī¼m in each of the three spatial dimensions. The tracking and vertexing software is fast and flexible, and easily adaptable to other functions, such as fast tracking for the trigger, or dedicated tracking for electrons that takes into account bremsstrahlung

    Alignment of the CMS tracker with LHC and cosmic ray data

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    Ā© CERN 2014 for the benefit of the CMS collaboration, published under the terms of the Creative Commons Attribution 3.0 License by IOP Publishing Ltd and Sissa Medialab srl. Any further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation and DOI.The central component of the CMS detector is the largest silicon tracker ever built. The precise alignment of this complex device is a formidable challenge, and only achievable with a significant extension of the technologies routinely used for tracking detectors in the past. This article describes the full-scale alignment procedure as it is used during LHC operations. Among the specific features of the method are the simultaneous determination of up to 200 000 alignment parameters with tracks, the measurement of individual sensor curvature parameters, the control of systematic misalignment effects, and the implementation of the whole procedure in a multi-processor environment for high execution speed. Overall, the achieved statistical accuracy on the module alignment is found to be significantly better than 10Ī¼m
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