Mapping the wavefunction of transition metal acceptor states in the GaAs surface

We utilize a single atom substitution technique with spectroscopic imaging in a scanning tunneling microscope (STM) to visualize the anisotropic spatial structure of magnetic and non-magnetic transition metal acceptor states in the GaAs (110) surface. The character of the defect states play a critical role in the properties of the semiconductor, the localization of the states influencing such things as the onset of the metal-insulator transition, and in dilute magnetic semiconductors the mechanism and strength of magnetic interactions that lead to the emergence of ferromagnetism. We study these states in the GaAs surface finding remarkable similarities between the shape of the acceptor state wavefunction for Mn, Fe, Co and Zn dopants, which is determined by the GaAs host and is generally reproduced by tight binding calculations of Mn in bulk GaAs [Tang, J.M. & Flatte, M.E., Phys. Rev. Lett. 92, 047201 (2004)]. The similarities originate from the antibonding nature of the acceptor states that arise from the hybridization of the impurity d-levels with the host. A second deeper in-gap state is also observed for Fe and Co that can be explained by the symmetry breaking of the surface.Comment: 19 pages, 6 figure

Aberrations in shift-invariant linear optical imaging systems using partially coherent fields

Here the role and influence of aberrations in optical imaging systems employing partially coherent complex scalar fields is studied. Imaging systems require aberrations to yield contrast in the output image. For linear shift-invariant optical systems, we develop an expression for the output cross-spectral density under the space-frequency formulation of statistically stationary partially coherentfields. We also develop expressions for the output cross{spectral density and associated spectral density for weak-phase, weak-phase-amplitude, and single-material objects in one transverse spatial dimension

IMC antecedents and the consequences of planned brand identity in higher education

Purpose – This study identifies IMC antecedents and the consequences of planned brand identity in the context of higher education, and empirically tests a number of hypotheses related to the constructs of these antecedents and consequences. Design/methodology/approach – A model of the IMC antecedents and consequences of planned brand identity was tested in a survey conducted among stakeholders in two London-based Universities. Structural equation modelling (SEM) was applied to gain insight into the various influences and relationships. Findings – The study identifies and confirms key constructs in planned brand identity. IMC antecedents of planned brand identity, such as brand elements, service attributes, public relations, and place/country-of-origin were found to positively influence the planned brand identity consequences of awareness, image, and reputation. However, websites, social media, advertising and direct marketing were not found to have significant influence. Research limitations/implications – The focus on two UK universities limits the generalisability of the findings. Future research should be conducted in other country settings in order to test the relationships identified in the present study. Also, future research may build on the study’s findings by investigating the attitudinal and behavioural consequences of brand identification in the higher education context. Practical implications – Professionals responsible for universities’ promotional and branding activities need to evaluate the relative contributions of the IMC antecedents of planned brand identity. Brand elements such as design, color and name, for example, should be reviewed to determine whether modifications are required in different international markets. The increasing prevalence of social media, one of the key antecedents of brand awareness, offers opportunities for universities to engage in brand co-creation by interacting with past, present and future students on relevant digital platforms. Finally, the place/country-of-origin cue is of particular relevance to institutions of higher education given the increasing numbers of students at both undergraduate and postgraduate levels who are choosing to study abroad (Melewar and Akel, 2005). The attraction of the United Kingdom as a country to study in, or the appeal of individual cities such as London, should be fully integrated into universities’ IMC strategies. Originality/value – The study makes two main contributions. First, we make a theoretical contribution by identifying the core IMC antecedents and consequences of planned brand identity for universities and from this extrapolate key directions for future research. Second, we indicate a number of managerial implications designed to assist in the formulation of improved professional practice

Integrating identity, strategy and communications for trust, loyalty and commitment

Purpose – This paper operationalize and juxtaposes variables related to identity, strategy and communications and then focuses on the impact of such integration on organizational stakeholders’ trust, loyalty and commitment. Design/methodology/approach – This research design utilises explanatory research at the preliminary stage, as informed by the literature and conceptual framework. The subsequent model was examined via a positivist survey carried out among stakeholders in high-end retail stores in London. Structural equation modelling (SEM) via AMOS was conducted to gain insight into the various influences and relationships. Findings – The results indicate that identity and strategy are key drivers of integrated corporate communication, and they serve to build stakeholder trust, loyalty and commitment. Originality/value – The paper shows that while practitioners have indicated that integrated marketing communication is important for organizations, there are a few other areas of concern with regard to consequences related to trust, loyalty and commitment, especially in a retail context. We empirically examined relationships between these constructs by validating a conceptual model employing SEM

A bibliometric investigation of service failure literature and a research agenda

Purpose - This research studies the citations made in service failure literature, and assesses the knowledge construction of this region of exploration to date. Design/methodology/approach - The bibliometric investigation assesses 416 service failure articles in business associated research. Multidimensional scaling (MDS) is employed to uncover the scope of the scholarly impacts that have helped understand the nature of the service failure literature. The establishment of knowledge in the service failure literature is revealed by analysing co-citation data to identify significant topical impacts. Findings - The theoretical model combines five areas with significant propositions for the future improvement of service failure as an area of investigation. The most important research themes in-service failure literature are service failure, service failure communication, the recovery process, recovery offer and intention. Research limitations/implications - Potential research concentrating on the service failure literature could use search terms improved from the literature review, or use a comparable approach whereby a board of well-informed scholars approved the keywords used. Practical implications - This paper is beneficial for any reader who is interested in understanding the components of the perception of justice and recovery and how it improves repurchase intention. Originality/value - The study seeks to influence resource and recovery-based concepts and utilises the five supporting knowledge groups to suggest a plan for future research that fills existing gaps and offers the possibility of expanding and enhancing the service failure literature

The Evolution of Legal Risks Pertaining to Patch Management and Vulnerability Management

This article begins with an overview, in non-technical terms, of the tools generally available and processes implemented for vulnerability management and patch management. Section II identifies some of the evolving security standards that regulators and plaintiffs may rely on to show that companies are legally required to have vulnerability management and patch management. Section III identifies U.S. legal implications of vulnerability management and patch management and factors that a court and regulators may consider

Quantifying errors due to frequency changes and target location uncertainty for radar refractivity retrievals

Radar refractivity retrievals can capture near-surface humidity changes, but noisy phase changes of the ground clutter returns limit the accuracy for both klystron- and magnetron-based systems. Observations with a C-band (5.6 cm) magnetron weather radar indicate that the correction for phase changes introduced by local oscillator frequency changes leads to refractivity errors no larger than 0.25 N units: equivalent to a relative humidity change of only 0.25% at 20°C. Requested stable local oscillator (STALO) frequency changes were accurate to 0.002 ppm based on laboratory measurements. More serious are the random phase change errors introduced when targets are not at the range-gate center and there are changes in the transmitter frequency (ΔfTx) or the refractivity (ΔN). Observations at C band with a 2-μs pulse show an additional 66° of phase change noise for a ΔfTx of 190 kHz (34 ppm); this allows the effect due to ΔN to be predicted. Even at S band with klystron transmitters, significant phase change noise should occur when a large ΔN develops relative to the reference period [e.g., ~55° when ΔN = 60 for the Next Generation Weather Radar (NEXRAD) radars]. At shorter wavelengths (e.g., C and X band) and with magnetron transmitters in particular, refractivity retrievals relative to an earlier reference period are even more difficult, and operational retrievals may be restricted to changes over shorter (e.g., hourly) periods of time. Target location errors can be reduced by using a shorter pulse or identified by a new technique making alternate measurements at two closely spaced frequencies, which could even be achieved with a dual–pulse repetition frequency (PRF) operation of a magnetron transmitter

A Multi-scale Bilateral Structure Tensor Based Corner Detector

9th Asian Conference on Computer Vision, ACCV 2009, Xi'an, 23-27 September 2009In this paper, a novel multi-scale nonlinear structure tensor based corner detection algorithm is proposed to improve effectively the classical Harris corner detector. By considering both the spatial and gradient distances of neighboring pixels, a nonlinear bilateral structure tensor is constructed to examine the image local pattern. It can be seen that the linear structure tensor used in the original Harris corner detector is a special case of the proposed bilateral one by considering only the spatial distance. Moreover, a multi-scale filtering scheme is developed to tell the trivial structures from true corners based on their different characteristics in multiple scales. The comparison between the proposed approach and four representative and state-of-the-art corner detectors shows that our method has much better performance in terms of both detection rate and localization accuracy.Department of ComputingRefereed conference pape

Concentration and δD of molecular hydrogen in boreal forests: Ecosystem-scale systematics of atmospheric H_2

We examined the concentration and δD of atmospheric H2 in a boreal forest in interior Alaska to investigate the systematics of high latitude soil uptake at ecosystem scale. Samples collected during nighttime inversions exhibited vigorous H_2 uptake, with concentration negatively correlated with the concentration of CO_2 (−0.8 to −1.2 ppb H_2 per ppm CO_2) and negatively correlated with δD of H_2. We derived H_2 deposition rates of between 2 to 12 nmol m^(−2) s^(−1). These rates are comparable to those observed in lower latitude ecosystems. We also derive an average fractionation factor, α = D:H_(residual)/D:H_(consumed) = 0.94 ± 0.01 and suggestive evidence that α depends on forest maturity. Our results show that high northern latitude soils are a significant sink of molecular hydrogen indicating that the record of atmospheric H_2 may be sensitive to changes in climate and land use