Showing papers by "Royal Holloway, University of London published in 2013"

Boson Sampling on a Photonic Chip

Abstract: Although universal quantum computers ideally solve problems such as factoring integers exponentially more efficiently than classical machines, the formidable challenges in building such devices motivate the demonstration of simpler, problem-specific algorithms that still promise a quantum speedup. We constructed a quantum boson-sampling machine (QBSM) to sample the output distribution resulting from the nonclassical interference of photons in an integrated photonic circuit, a problem thought to be exponentially hard to solve classically. Unlike universal quantum computation, boson sampling merely requires indistinguishable photons, linear state evolution, and detectors. We benchmarked our QBSM with three and four photons and analyzed sources of sampling inaccuracy. Scaling up to larger devices could offer the first definitive quantum-enhanced computation.

A large-scale evaluation of computational protein function prediction

Abstract: Automated annotation of protein function is challenging. As the number of sequenced genomes rapidly grows, the overwhelming majority of protein products can only be annotated computationally. If computational predictions are to be relied upon, it is crucial that the accuracy of these methods be high. Here we report the results from the first large-scale community-based critical assessment of protein function annotation (CAFA) experiment. Fifty-four methods representing the state of the art for protein function prediction were evaluated on a target set of 866 proteins from 11 organisms. Two findings stand out: (i) today's best protein function prediction algorithms substantially outperform widely used first-generation methods, with large gains on all types of targets; and (ii) although the top methods perform well enough to guide experiments, there is considerable need for improvement of currently available tools.

Measurement of an excess of B̄→D(*) τ-ν̄τ decays and implications for charged Higgs bosons

Abstract: The concept for this analysis is to a large degree based on earlier BABAR work and we acknowledge the guidance provided by M. Mazur. The authors consulted with theorists A. Datta, S. Westhoff, S. Fajfer, J. Kamenik, and I. Nisandzic on the calculations of the charged Higgs contributions to the decay rates. We are grateful for the extraordinary contributions of our PEP-II colleagues in achieving the excellent luminosity and machine conditions that have made this work possible. The success of this project also relied critically on the expertise and dedication of the computing organizations that support BABAR. The collaborating institutions wish to thank SLAC for its support and the kind hospitality extended to them. This work is supported by the U.S. Department of Energy and National Science Foundation, the Natural Sciences and Engineering Research Council (Canada), the Commissariat a l'Energie Atomique and Institut National de Physique Nucleaire et de Physique des Particules (France), the Bundesministerium fur Bildung und Forschung and Deutsche Forschungsgemeinschaft (Germany), the Istituto Nazionale di Fisica Nucleare (Italy), the Foundation for Fundamental Research on Matter (Netherlands), the Research Council of Norway, the Ministry of Education and Science of the Russian Federation, Ministerio de Economia y Competitividad (Spain), and the Science and Technology Facilities Council (United Kingdom). Individuals have received support from the Marie-Curie IEF program (European Union) and the A. P. Sloan Foundation (USA).

Biogenesis and homeostasis of chloroplasts and other plastids

Abstract: Chloroplasts are the ancestral members of the plastid organelle family. Their identity, division and biogenesis require the import of nucleus-encoded proteins and tight coordination between the organellar genetic system and the nucleocytosolic system. The ubiquitin–proteasome system also links plastid homeostasis and biogenesis to organismal development. Chloroplasts are the organelles that define plants, and they are responsible for photosynthesis as well as numerous other functions. They are the ancestral members of a family of organelles known as plastids. Plastids are remarkably dynamic, existing in strikingly different forms that interconvert in response to developmental or environmental cues. The genetic system of this organelle and its coordination with the nucleocytosolic system, the import and routing of nucleus-encoded proteins, as well as organellar division all contribute to the biogenesis and homeostasis of plastids. They are controlled by the ubiquitin–proteasome system, which is part of a network of regulatory mechanisms that integrate plastid development into broader programmes of cellular and organismal development.

Improved luminosity determination in pp collisions at root s=7 TeV using the ATLAS detector at the LHC

Abstract: The luminosity calibration for the ATLAS detector at the LHC during pp collisions at root s = 7 TeV in 2010 and 2011 is presented. Evaluation of the luminosity scale is performed using several luminosity-sensitive detectors, and comparisons are made of the long-term stability and accuracy of this calibration applied to the pp collisions at root s = 7 TeV. A luminosity uncertainty of delta L/L = +/- 3.5 % is obtained for the 47 pb(-1) of data delivered to ATLAS in 2010, and an uncertainty of delta L/L = +/- 1.8 % is obtained for the 5.5 fb(-1) delivered in 2011.

Introduction to Industrial Control Networks

Abstract: An industrial control network is a system of interconnected equipment used to monitor and control physical equipment in industrial environments. These networks differ quite significantly from traditional enterprise networks due to the specific requirements of their operation. Despite the functional differences between industrial and enterprise networks, a growing integration between the two has been observed. The technology in use in industrial networks is also beginning to display a greater reliance on Ethernet and web standards, especially at higher levels of the network architecture. This has resulted in a situation where engineers involved in the design and maintenance of control networks must be familiar with both traditional enterprise concerns, such as network security, as well as traditional industrial concerns such as determinism and response time. This paper highlights some of the differences between enterprise and industrial networks, presents a brief history of industrial networking, gives a high level explanation of some operations specific to industrial networks, provides an overview of the popular protocols in use and describes current research topics. The purpose of this paper is to serve as an introduction to industrial control networks, aimed specifically at those who have had minimal exposure to the field, but have some familiarity with conventional computer networks.

Observation of Associated Near-Side and Away-Side Long-Range Correlations in √sNN=5.02 TeV Proton-Lead Collisions with the ATLAS Detector

Abstract: Two-particle correlations in relative azimuthal angle (Delta phi) and pseudorapidity (Delta eta) are measured in root S-NN = 5.02 TeV p + Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1 mu b(-1) of data as a function of transverse momentum (p(T)) and the transverse energy (Sigma E-T(Pb)) summed over 3.1 < eta < 4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2 < vertical bar Delta eta vertical bar < 5) "near-side" (Delta phi similar to 0) correlation that grows rapidly with increasing Sigma E-T(Pb). A long-range "away-side" (Delta phi similar to pi) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small Sigma E-T(Pb), is found to match the near-side correlation in magnitude, shape (in Delta eta and Delta phi) and Sigma E-T(Pb) dependence. The resultant Delta phi correlation is approximately symmetric about pi/2, and is consistent with a dominant cos2 Delta phi modulation for all Sigma E-T(Pb) ranges and particle p(T).

The role of tourists' emotional experiences and satisfaction in understanding behavioral intentions

Abstract: Modeling behavioral intentions remain an important area of research in tourism. This study empirically tests a model linking tourists' emotional experiences, satisfaction and behavioral intentions. The model proposes that satisfaction mediates the relationship between tourists' emotional experiences and behavioral intentions. Data were collected from international tourists visiting Petra, a UNESCO world heritage site. Contrary to theoretical predictions, results do not support the mediating effect of satisfaction on the relationship between emotions (joy, love, positive surprise, and unpleasantness) and behavioral intentions. Findings offer important strategic marketing implications for Petra in relation to branding and managing destination experiences.

Organizing Corporate Social Responsibility in Small and Large Firms: Size Matters

Abstract: Based on the findings of a qualitative empirical study of corporate social responsibility (CSR) in Swiss MNCs and SMEs, we suggest that smaller firms are not necessarily less advanced in organizing CSR than large firms. Results according to theoretically derived assessment frameworks illustrate the actual implementation status of CSR in organizational practices. We propose that small firms possess several organizational characteristics that are favorable for promoting the internal implementation of CSR-related practices in core business functions, but constrain external communication and reporting about CSR. In contrast, large firms possess several characteristics that are favorable for promoting external communication and reporting about CSR, but at the same time constrain internal implementation. We sketch a theoretical explanation of these differences in organizing CSR in MNCs and SMEs based on the relationship between firm size and relative organizational costs.

Validation of the Emotiv EPOC® EEG gaming system for measuring research quality auditory ERPs

Abstract: Background. Auditory event-related potentials (ERPs) have proved useful in investigating the role of auditory processing in cognitive disorders such as developmental dyslexia, specific language impairment (SLI), attention deficit hyperactivity disorder (ADHD), schizophrenia, and autism. However, laboratory recordings of auditory ERPs can be lengthy, uncomfortable, or threatening for some participants – particularly children. Recently, a commercial gaming electroencephalography (EEG) system has been developed that is portable, inexpensive, and easy to set up. In this study we tested if auditory ERPs measured using a gaming EEG system (Emotiv EPOC®, www.emotiv.com) were equivalent to those measured by a widely-used, laboratory-based, research EEG system (Neuroscan). Methods. We simultaneously recorded EEGs with the research and gaming EEG systems, whilst presenting 21 adults with 566 standard (1000 Hz) and 100 deviant (1200 Hz) tones under passive (non-attended) and active (attended) conditions. The onset of each tone was marked in the EEGs using a parallel port pulse (Neuroscan) or a stimulus-generated electrical pulse injected into the O1 and O2 channels (Emotiv EPOC®). These markers were used to calculate research and gaming EEG system late auditory ERPs (P1, N1, P2, N2, and P3 peaks) and the mismatch negativity (MMN) in active and passive listening conditions for each participant. Results. Analyses were restricted to frontal sites as these are most commonly reported in auditory ERP research. Intra-class correlations (ICCs) indicated that the morphology of the research and gaming EEG system late auditory ERP waveforms were similar across all participants, but that the research and gaming EEG system MMN waveforms were only similar for participants with non-noisy MMN waveforms (N = 11 out of 21). Peak amplitude and latency measures revealed no significant differences between the size or the timing of the auditory P1, N1, P2, N2, P3, and MMN peaks. Conclusions. Our findings suggest that the gaming EEG system may prove a valid alternative to laboratory ERP systems for recording reliable late auditory ERPs (P1, N1, P2, N2, and the P3) over the frontal cortices. In the future, the gaming EEG system may also prove useful for measuring less reliable ERPs, such as the MMN, if the reliability of such ERPs can be boosted to the same level as late auditory ERPs.

Quantum-Bayesian coherence

Abstract: In the quantum-Bayesian interpretation of quantum theory (or QBism), the Born rule cannot be interpreted as a rule for setting measurement-outcome probabilities from an objective quantum state. But if not, what is the role of the rule? In this paper, the argument is given that it should be seen as an empirical addition to Bayesian reasoning itself. Particularly, it is shown how to view the Born rule as a normative rule in addition to usual Dutch-book coherence. It is a rule that takes into account how one should assign probabilities to the consequences of various intended measurements on a physical system, but explicitly in terms of prior probabilities for and conditional probabilities consequent upon the imagined outcomes of a special counterfactual reference measurement. This interpretation is exemplified by representing quantum states in terms of probabilities for the outcomes of a fixed, fiducial symmetric informationally complete measurement. The extent to which the general form of the new normative rule implies the full state-space structure of quantum mechanics is explored.

Institutions and Organisations

Abstract: It would be misleading to posit a cohesive British film industry in any period, but the 1970s were characterised by factionalism and polarisation. As well as internal opposing factions, the film industry faced competition not just from the Americans who were poised to take advantage of the weak domestic industry but also from television, which had become the leisure activity of choice for the British public.

Natural Resources and Local Communities: Evidence from a Peruvian Gold Mine

Abstract: This paper examines the local economic impact of Yanacocha, a large gold mine in Northern Peru. Using annual household data from 1997 to 2006, we find evidence of a positive effect of the mine’s demand for local inputs on real income. The effects are only present in the supply market and surrounding areas, and reach unskilled workers in nonmining sectors. Consistent with a general equilibrium framework, we also find an increase in the local price of nontradable goods. Taken together, our results underline the potential of backward linkages from extractive industries to create positive spillovers in less developed economies. (JEL L72, O13, O18, Q32, Q33, R11) The grudge against what has become known as the “enclave” type of development is due to this ability of primary products from mines, wells, and plantations to slip out of a country without leaving much of a trace in the rest of the economy. — Hirschman (1958, 110)

The Relationship Between Line Manager Behavior, Perceived HRM Practices, and Individual Performance: Examining the Mediating Role of Engagement

Abstract: This article examines the role played by line managers in the link between HRM practices and individual performance outcomes. Drawing on social exchange theory, the authors test a mediated model linking perceived line manager behavior and perceived human resource management practices with employee engagement and individual performance. The study focuses on two self-report measures of individual performance; task performance and innovative work behavior. Two studies with a total of 1,796 participants were conducted in service-sector organizations in the United Kingdom and analyzed using structural equation modeling. The data reveal that perceived line manager behavior and perceived HRM practices are linked with employee engagement. In turn, employee engagement is strongly linked to individual performance and fully mediates the link between both perceived HRM practices and perceived line manager behavior and self-report task performance (study 1), as well as self-report innovative work behavior (study 2). The findings show the significance of the line manager in the HRM-performance link, and the mediating role played by employee engagement. © 2013 Wiley Periodicals, Inc.

Six Decades of Top Economics Publishing: Who and How?

Abstract: Presenting data on all full-length articles in the three top general economics journals for one year in each decade 1960s–2010s, I analyze changes in patterns of coauthorship, age structure and methodology, and their possible causes. The distribution of number of authors has shifted steadily rightward. In the last two decades, the fraction of older authors has almost quadrupled. Top journals are publishing many fewer papers that represent pure theory, regardless of subfield, somewhat less empirical work based on publicly available data sets, and many more empirical studies based on data collected by the author(s) or on laboratory or field experiments. (JEL A14)

Can cognitive models explain brain activation during word and pseudoword reading? A meta-analysis of 36 neuroimaging studies.

Abstract: Reading in many alphabetic writing systems depends on both item-specific knowledge used to read irregular words (sew, yacht) and generative spelling-sound knowledge used to read pseudowords (tew, yash). Research into the neural basis of these abilities has been directed largely by cognitive accounts proposed by the dual-route cascaded and triangle models of reading. We develop a framework that enables predictions for neural activity to be derived from cognitive models of reading using 2 principles: (a) the extent to which a model component or brain region is engaged by a stimulus and (b) how much effort is exerted in processing that stimulus. To evaluate the derived predictions, we conducted a meta-analysis of 36 neuroimaging studies of reading using the quantitative activation likelihood estimation technique. Reliable clusters of activity are localized during word versus pseudoword and irregular versus regular word reading and demonstrate a great deal of convergence between the functional organization of the reading system put forward by cognitive models and the neural systems activated during reading tasks. Specifically, left-hemisphere activation clusters are revealed reflecting orthographic analysis (occipitotemporal cortex), lexical and/or semantic processing (anterior fusiform, middle temporal gyrus), spelling-sound conversion (inferior parietal cortex), and phonological output resolution (inferior frontal gyrus). Our framework and results establish that cognitive models of reading are relevant for interpreting neuroimaging studies and that neuroscientific studies can provide data relevant for advancing cognitive models. This article thus provides a firm empirical foundation from which to improve integration between cognitive and neural accounts of the reading process.

Strategic Narratives: Communication Power and the New World Order

Abstract: 1. Introduction. 2. Actors in Strategic Narratives. 3. Strategic Narratives of International Order. 4. Contestation. 5.Information Infrastructure. 6. Conclusions: Thinking Ahead.

Search for direct third-generation squark pair production in final states with missing transverse momentum and two b-jets in √s = 8 TeV pp collisions with the ATLAS detector

Abstract: The results of a search for pair production of supersymmetric partners of the Standard Model third-generation quarks are reported. This search uses 20.1 fb-1 of pp collisions at sqrt{s}=8 TeV collected by the ATLAS experiment at the Large Hadron Collider. The lightest bottom and top squarks (b1 and t1 respectively) are searched for in a final state with large missing transverse momentum and two jets identified as originating from b-quarks. No excess of events above the expected level of Standard Model background is found. The results are used to set upper limits on the visible cross section for processes beyond the Standard Model. Exclusion limits at the 95% confidence level on the masses of the third-generation squarks are derived in phenomenological supersymmetric R-parity-conserving models in which either the bottom or the top squark is the lightest squark. The b1 is assumed to decay via b1->b chi0 and the t via t1->b chipm, with undetectable products of the subsequent decay of the chipm due to the small mass splitting between the chipm and the chi0.

Visual Management Studies: Empirical and Theoretical Approaches*

Abstract: The field of visual research in management studies is developing rapidly and has reached a point of maturity where it is useful to bring together and evaluate existing work in this area and to critically assess its current impact and future prospects. Visual research is broadly defined to encompass a variety of forms, including pictures, graphs, film, web pages and architecture. It also incorporates work from several sub-disciplines (organization studies, marketing, accounting, human resources, tourism and IT), and includes research based on pre-existing visual material and studies that use researcher-generated visual data. The authors begin by considering the growing recognition of the visual turn in management research as a counterweight to the linguistic turn, while also discussing reasons for resistance to visual approaches. Next, they review research that uses visual methods to study management and organization and suggest that visual management studies may be categorized according to whether methods used are empirically driven or theory based. This categorization highlights the philosophical, theoretical and interdisciplinary underpinnings of visual management studies. It also enables the visual to be accorded a status equivalent to linguistic meaning, through dispelling the realist assumptions that have impeded analytical development of visual management studies to date.

Search for dark matter candidates and large extra dimensions in events with a jet and missing transverse momentum with the ATLAS detector

Abstract: A search for new phenomena in events with a high-energy jet and large missing transverse momentum is performed using data from proton-proton collisions at root s = 7 TeV with the ATLAS experiment at the Large flatiron Collider. Four kinematic regions are explored using a dataset corresponding to an integrated luminosity of 4.7 fb(-1). No excess of events beyond expectations from Standard Model processes is observed, and limits are set on large extra dimensions and the pair production of dark matter particles.

Employee voice and engagement: connections and consequences

Abstract: This paper considers the relationship between employee voice and employee engagement. Employee perceptions of voice behaviour aimed at improving the functioning of the work group are found to have both a direct impact and an indirect impact on levels of employee engagement. Analysis of data from two organisations confirms that the direct connection between perceptions of voice behaviour and engagement is mediated by both employee trust in senior management and the employee–line manager relationship. Key concepts are outlined, and the implications of the findings for future research and for the management of engagement are discussed.

Anti-Consumption as the Study of Reasons against:

Abstract: Anti-consumption studies are gaining in popularity, but doubt remains as to whether they can add anything unique to consumer research and marketing that other similar topics cannot. This article attempts to explain the distinctive nature of anti-consumption and how it can contribute to the understanding of marketing beyond other related phenomena, such as ethical consumption, environmental consumption, consumer resistance, and symbolic consumption. Drawing upon reasons theory, the article contends that the “reasons against” consumption are not always the logical opposite of the “reasons for” consumption and there are important differences between phenomena of negation and affirmation. By focusing on the reasons against consumption, anti-consumption research acts as a lens that scholars and practitioners may use to view similar phenomena in a new light. The article illustrates this point by offering anti-consumption as an overarching perspective that spans a range of behavioral and thematic contexts, there...