122,757 research outputs found

    Las Casas et le licencié Cerrato

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    Bataillon Marcel. Las Casas et le licencié Cerrato . In: Bulletin Hispanique, tome 55, n°1, 1953. pp. 79-87

    Entanglement degradation in the presence of Markovian noise: A statistical analysis

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    Adopting a statistical approach we study the degradation of entanglement of a quantum system under the action of an ensemble of randomly distributed Markovian noise. This enables us to address scenarios where only limited information is available on the mechanisms that rule the noisy evolution of the model. As an application, we characterize the statistic of entanglement deterioration for a quantum memory formed by n qudits that undergo randomly distributed local, uniform, Markovian noise evolution

    Panel Data Tests of PPP. A Critical Overview

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    This paper reviews panel unit root and cointegration tests in the context of PPP. It highlights various drawbacks of existing methods. First, unit root tests suffer from severe size distortions in the presence of negative moving average errors. Second, the common demeaning procedure to correct for the bias resulting from homogeneous cross-sectional dependence is not effective; more worryingly, it introduces cross-correlation when it is not already present. Third, standard corrections for the case of heterogeneous cross-sectional dependence do not generally produce consistent estimators. Fourth, if there is between-group correlation in the innovations, the SURE estimator is affected by similar problems to FGLS methods, and does not necessarily outperform OLS. Finally, cointegration between different groups in the panel could also be a source of size distortions. We offer some empirical guidelines to deal with these problems, but conclude that panel methods are unlikely to solve the PPP puzzle.Purchasing Power Parity (PPP), Panel unit root and cointegration tests, Cross-sectional dependence

    The Multinational Enterprise as an Internal Market System

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    This paper builds on Birkinshaw’s model of multinational enterprise (MNE) as an internal market system [Birkinshaw, J. (2000). Entrepreneurship in the global firm. London: Sage]. This model addresses the issues related to the emergence of market-based mechanisms of coordination within the MNEs and the strategic decisions that affect internal competition. Birkinshaw argues that subsidiaries simultaneously participate in three different internal markets within an MNE:a market for intermediate goods and services, one for charters and another for competencies and practices. The goal of the paper is to expand Birkinshaw’s concept of internal market and analyze the logic behind internal competition by considering more fully existing literature and developing an organizing framework to position such a model within that literature. There is specific focus on discussing how the internal market model relates to modern network-based configurations of the MNE. In addition, the study shows that factors affecting the extent to which each of the three internal markets is established can be better understood if we link such a model to the contributions developed by three mainstreams of research: internalization theory, resource-based view and organizational learning literatur

    La collaborazione tra università e industria: un’indagine sui brevetti co-generati in Italia

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    Il sistema della ricerca universitaria mostra un significativo incremento nella capacità di generare nuove brevetti. Tuttavia, i tassi di valorizzazione commerciale di tali brevetti da parte delle imprese appaiono ancora piuttosto limitati. Risulta, pertanto, interessante investigare i fattori che possono favorire il coinvolgimento delle imprese nella ricerca accademica finalizzata alla produzione di innovazioni brevettabili. Sulla base di un campione di 282 brevetti, provenienti da docenti appartenenti a sette università italiane, il lavoro analizza l’incidenza di tre fattori sulla collaborazione tra ricerca e industria: a) la qualità della ricerca accademica dei docenti-inventori; b) la capacità innovativa del sistema industriale nella Regione dell’ateneo; c) l’esistenza di specifici cluster tecnologici su base locale. I risultati dell’analisi empirica suggeriscono che i fattori legati al contesto regionale ed al tessuto imprenditoriale locale giocano un ruolo significativo nel favorire il coinvolgimento delle imprese nella produzione di brevetti con docenti universitari, mentre la qualità della ricerca accademica non sembra influenzare la decisione delle imprese di collaborare con i docenti universitari.The academic research system shows a significant increase in the generation of new patents, but the capacity to transfer these patents to firms interested in their economic exploitation is still limited. It is therefore interesting to investigate the factors affecting firms’ involvement in the academic research that could lead to patentable results. Drawing on data from a sample of 282 patents from academic inventors of seven Italian universities, this paper focuses on three possible drivers of university-industry collaboration: a) the quality of the research of academic inventors; b) the innovative capability of the industrial system in the Region where the university is located; c) the existence of a technology cluster in the university’s local context. Our results suggest that factors relating to the local industrial environment play a significant role in favoring the industry involvement in academic patents, while the quality of research does not turn into significantly affect firms’ decisions to collaborate with academic researchers

    Trust, control, and value creation in strategic networks of SMEs

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    This paper investigates the role of trust and control in networks of small and medium-sized enterprises (SMEs), with a focus on both their direct and interaction effects on value creation. To delve into the interplay between trust and control, we unpack control mechanisms into three different forms: output, process, and social control. Our hypotheses are tested on a sample of 58 Italian SME networks based on formal agreements. Results show that the competitiveness and sustainability of inter-firm networks require trust-based relationships among entrepreneurs. Additionally, the adoption of output control mechanisms reinforces the positive link between trust and value creation, whereas a substitution effect exists between trust and process control and, with limited significance, between trust and social control

    Surface functionalized N-C-TiO2/C nanocomposites derived from metal-organic framework in water vapour for enhanced photocatalytic H2 generation

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    Surface-functionalized nitrogen/carbon co-doped polymorphic TiO2 phase junction nanoparticles uniformly distributed in porous carbon matrix were synthesized by a simple one-step pyrolysis of titanium based metal–organic framework (MOF), NH2-MIL-125(Ti) at 700 °C under water vapour atmosphere. Introducing water vapour during the pyrolysis of NH2-MIL-125(Ti) not only functionalizes the derived porous carbon matrix with carboxyl groups but also forms additional oxygen-rich N like interstitial/intraband states lying above the valence band of TiO2 along with the self-doped carbon, which further narrows the energy band gaps of polymorphic TiO2 nanoparticles that enhance photocatalytic charge transfer efficiency. Without co-catalyst, sample N-C-TiO2/CArW demonstrates H2 evolution activity of 426 µmol gcat-1 h−1, which remarkably outperforms commercial TiO2 (P-25) and N-C-TiO2/CAr with a 5-fold and 3-fold H2 generation, respectively. This study clearly shows that water vapour atmosphere during the pyrolysis increases the hydrophilicity of the Ti-MOF derived composites by functionalizing porous carbon matrix with carboxylic groups, as well as enhancing the electrical conductivity and charge transfer efficiency due to the formation of additional localized oxygen-rich N like interstitial/intraband states. This work also demonstrates that by optimizing the anatase–rutile phase composition of the TiO2 polymorphs, tuning the energy band gaps by N/C co-doping and functionalizing the porous carbon matrix in the N-C-TiO2/C nanocomposites, the photocatalytic H2 generation activity can be further enhanced

    A Multi-Language Comparison of Influences on Author Verification using Character N-Grams

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    We create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc

    Appropriate Similarity Measures for Author Cocitation Analysis

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    We provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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