697 research outputs found

    Importance of the V 3d-O 2p hybridization in the Mott-Hubbard material V2O3

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    We studied the changes in the electronic structure of V2O3 using a cluster model. The calculations included fluctuations from the coherent band in the metallic phase, and non-local Mott-Hubbard fluctuations in the insulating phase. The incoherent structure is mostly related to the usual ligand screening channel (3d2L). The coherent peak in the metallic phase corresponds to coherent band fluctuations (3d2C). The non-local screened state in the insulating phase (3d2D) appears at higher energies, opening the band gap. The photon energy dependence of the spectra is mostly due to the relative V 3d and O 2p cross sections. The present model reproduces also the observed changes in the V 1s core-level spectra. The above results suggest that the Mott-Hubbard transition in V2O3 requires a multi-band model.Comment: 4 pages, 4 figure

    Temperature dependent Eu 3d-4f X-ray Absorption and Resonant Photoemission Study of the Valence Transition in EuNi2(Si0.2Ge0.8)2EuNi_2(Si_{0.2}Ge_{0.8})_2

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    We study the mixed valence transition (TTv_{v} \sim80 K) in EuNi2_{2}(Si0.2_{0.2}Ge0.8_{0.8})2_{2} using Eu 3d4fd-4f X-ray absorption spectroscopy (XAS) and resonant photoemission spectroscopy (RESPES). The Eu2+^{2+} and Eu3+^{3+} main peaks show a giant resonance and the spectral features match very well with atomic multiplet calculations. The spectra show dramatic temperature (TT)-dependent changes over large energies (\sim10 eV) in RESPES and XAS. The observed non-integral mean valencies of \sim2.35 ±\pm 0.03 (TT = 120 K) and \sim2.70 ±\pm 0.03 (TT = 40 K) indicate homogeneous mixed valence above and below TTv_{v}. The redistribution between Eu2+^{2+}4f74f^7+[spd]0[spd]^0 and Eu3+^{3+}4f64f^6+[spd]1[spd]^1 states is attributed to a hybridization change coupled to a Kondo-like volume collapse.Comment: 4 pages, 3 figure

    Evaluation of subsidiary marketing performance: combining process and outcome performance metrics

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    Abstract Issues in evaluating marketing performance and devising appropriate metrics for measurement have taken center stage in marketing thought and practice in recent years. We propose an empirical model that enables a multinational enterprise (MNE) to assess the marketing performance of its subsidiaries, taking into explicit consideration the fact that tactical actions by subsidiaries contribute to the creation of assets that can be harnessed for marketing outcomes. Thus, our model captures the asset creation abilities of marketing expenditures and also takes in to account the environmental differences of the context in which each MNE subsidiary operates. We evaluate comparative, overall, and process-level (creation of market assets and market yield) marketing performance in the context of multi-country operations. This simultaneous examination of marketing process and marketing outcome performance enables a global corporation to gain strategic, operational, and diagnostic insights into the performance of its subsidiaries. Our approach is empirically illustrated with an evaluation of the marketing performance of subsidiaries of a large global corporation. Keywords Multinational performance evaluations . Marketing metrics . Outcome measures . Performance measures . Standardization There is now more pressure on marketing scholars and practitioners to demonstrate that the marketing function contributes to shareholder value for the firm (Doyle 2000; At the same time, the justification of marketing expenditures and the assessment of marketing performance is particularly complex for multinational enterprises (MNE). Although MNE performance assessment is clouded by various economic and accounting exposure risks, such as translation and transaction risk

    Bulk Electronic structure of Na0.35_{0.35}CoO2_{2}.1.3H2_{2}O

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    High-energy (hν\nu = 5.95 keV) synchrotron Photoemission spectroscopy (PES) is used to study bulk electronic structure of Na0.35_{0.35}CoO2_{2}.1.3H2_{2}O, the layered superconductor. In contrast to 3-dimensional doped Co oxides, Co 2p\it{2p} core level spectra show well-separated Co3+^{3+} and Co4+^{4+} ions. Cluster calculations suggest low spin Co3+^{3+} and Co4+^{4+} character, and a moderate on-site Coulomb correlation energy Udd_{dd}\sim3-5.5 eV. Photon dependent valence band PES identifies Co 3d\it{3d} and O 2p\it{2p} derived states, in near agreement with band structure calculations.Comment: 4 pages 4 figures Revised text added referenc

    Choice Models and Customer Relationship Management

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    Customer relationship management (CRM) typically involves tracking individual customer behavior over time, and using this knowledge to configure solutions precisely tailored to the customers' and vendors' needs. In the context of choice, this implies designing longitudinal models of choice over the breadth of the firm's products and using them prescriptively to increase the revenues from customers over their lifecycle. Several factors have recently contributed to the rise in the use of CRM in the marketplacePeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47023/1/11002_2005_Article_5892.pd

    The impact of customer-specific marketing expenses on customer retention and customer profitability

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    We study the effects of customer-specific marketing expenses on customer retention and customer profitability in a business-to-business setting. Using data from a company providing hygiene services, we look at the impact of a hitherto unstudied type of expense targeted at individual customer relationships: the offering of free equipment to customers. The data allow tracking the activities performed in more than 4,500 customer relationships over a period of 4 years. Retention rates are higher for customers targeted with free equipment, but this effect results from an interaction with customer size. First-order dynamic panel data analyses show that the impact of targeted marketing expenses on customer dollar profit is positive for large customers, but there is no effect for smaller customers. Thus, targeted marketing expenses seem to be a tool for relationship maintenance rather than customer development: they help in retaining large customers that generate more profit, but they do not seem to work in developing new customers into larger, more profitable ones

    Issues in the estimation and application of latent structure models of choice

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    Our paper provides a brief review and summary of issues and advances in the use of latent structure and other finite mixture models in the analysis of choice data. Focus is directed to three primary areas: (1) estimation and computational issues, (2) specification and interpretation issues, and (3) future research issues. We comment on what latent structure models have promised, what has been, to date, delivered, and what we should look forward to in the future.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47160/1/11002_2005_Article_BF00999208.pd

    Premature ventricular contractions originating from the left ventricular septum: Results of Radiofrequency Catheter Ablation in twenty patients

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    <p>Abstract</p> <p>Background</p> <p>RFCA has been established as an effective and curative therapy for severely symptomatic PVC from the outflow tract in structurally normal hearts. However, it is unknown whether PVCs originating from the left ventricular septum, are effectively eliminated by RFCA. This study aimed to investigate electrophysiologic characteristics and effects of Radiofrequency catheter ablation (RFCA) for patients with symptomatic premature ventricular contraction (PVC) originating from the left ventricular septum without including fascicular PVCs.</p> <p>Methods</p> <p>Characteristics of body surface electrocardiogram (ECG) and electrophysiologic recordings endocardiogram in a successful RFCA target were analyzed in 20 patients with symptomatic PVCs originating from the left ventricular septum. RFCA was performed using pace mapping and activation mapping.</p> <p>Results</p> <p>The QRS morphology of PVCs originating from the left ventricular septum is similar to that seen in fascicular tachycardia. Most of the PVCs originated from the left septum appears in the form of ventricular parasystole. The incidence of ventricular parasystole was 70%. Sustained ventricular tachycardia was not inducible by electrical stimulation and isoproterenol infusion in all 20 patients, ablation at the site recording the earliest Purkinje potential was not effective in all 20 patients, and Purkinje potentials were not identified at successful sites during point mapping. Sixteen patients were successful with RFCA using pace mapping and activation mapping, 3 failed, and 1 recurrent.</p> <p>Conclusion</p> <p>Although the ECG characteristics of the PVCs arising from the left ventricular septum are similar to that seen in fascicular tachycardia, the electrophysiologic characteristics are different between the two types of PVCs. The distinguishing characteristic of the PVCs is that Purkinje potentials were not present at the site of successful ablation, suggesting a myocardial as opposed to fascicular substrate. RFCA is an effective curative therapy for symptomatic PVCs originating from the left ventricular septum (not from the left anterior and posterior fascicle).</p
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