Selective d-state Conduction Blocking in Nickel Nanocontacts

The lowest conductance step for a Ni nanocontact is anomalously small in comparison with the large expected number of conducting channels. We present electronic structure calculations for an extremely idealized Ni nanobridge consisting of just a monatomic nanowire. Our calculations show that no less than eight single spin bands cross the Fermi level in a nonmagnetic Ni monatomic wire, dropping marginally to seven in the more stable, fully ferromagnetic state. However, when we build in the wire a magnetization reversal, or domain wall, by forcing the net magnetization to be zero, we suddenly find that d electrons selectively cease to propagate across the wall. s electron propagation remains, and can account for the small observed conductance steps.Comment: 9 pages, 4 figures, Surface Science, to appea

Cocriação de Valor no Turismo: Validação e Replicação de Escala em Relação à Intenção de Recomendação Boca-a-Boca

This study aimed to validate for the Brazilian context a value co-creation scale directed towards tourism (Busser & Shulga, 2018) and also to measure its effects in relation to the intention of word-of-mouth recommendation. The methodological procedures adopted included translation of the original scale, face validation, adaptations to the research object and data analysis through structural equation modeling (SEM). The sample comprised 210 tourists who have experienced tourism experiences in the last 02 years. The data collection instrument was made using the Google Forms platform and submitted to respondents in the second half of 2018. Among the results: a) All 5 dimensions of the original scale were supported in this research (significance, collaboration, contribution, recognition and affective response) and b) the scale presented an R² of 0.614, explaining 61% of the intention of mouth-to-mouth recommendation.Esta investigación tuvo como objetivo validar para el contexto brasileño una escala de co-creación de valor dirigida al turismo (Busser & Shulga, 2018) y también medir sus efectos en relación con la intención de recomendación de boca en boca. Los procedimientos metodológicos adoptados incluyeron la traducción de la escala original, validación facial, adaptaciones al objeto de investigación y análisis de datos a través del modelado de ecuaciones estructurales (SEM). La muestra incluyó a 210 turistas que han experimentado experiencias turísticas en los últimos 02 años. El instrumento de recopilación de datos se realizó utilizando la plataforma Google Forms y se presentó a los encuestados en la segunda mitad de 2018. Entre los resultados: a) Las 5 dimensiones de la escala original fueron respaldadas en esta investigación (importancia, colaboración, contribución, reconocimiento y respuesta afectiva) yb) la escala presentó un R² de 0.614, lo que explica el 61% de la intención de la recomendación boca a boca.Este estudo teve como objetivo validar para o contexto brasileiro uma escala de cocriação de valor direcionada para o turismo (Busser & Shulga, 2018) e também mensurar os seus efeitos em relação à intenção de recomendação boca-a-boca (WoM). Os procedimentos metodológicos adotados incluíram tradução da escala original, validação de face, adaptações ao objeto de pesquisa e análise de dados por meio de modelagem de equações estruturais (MEE). A amostra compreendeu 210 turistas que vivenciaram experiências de turismo nos últimos 02 anos. O instrumento de coleta de dados foi feito pela plataforma Google Forms e submetido aos respondentes no segundo semestre de 2018. Entre os resultados: a) Todas as 5 dimensões da escala original foram suportadas nesta pesquisa (significância, colaboração, contribuição, reconhecimento e resposta afetiva) e b) a escala apresentou um R² de 0,611, explicando 61% da intenção de recomendação boca-a-boca

Colliding Kaluza-Klein Bubbles

We construct an exact solution describing the collision of two Kaluza-Klein "bubbles of nothing" in 3+1 dimensions. When the bubbles collide, a curvature singularity forms which is hidden inside an event horizon. However, unlike the formation of ordinary black holes, in this case the spacetime resembles the entire maximally extended Schwarzschild solution. We also point out that there are inequivalent bubbles that can be constructed from Kerr black holes.Comment: 20 pages, v2: minor error correcte

Gestão de stakeholders: evidências no desempenho das empresas de capital aberto

Purpose: This study consists of empirical evidence from stakeholder management in the performance indicators of publicly traded companies. Design/methodology/approach: The methodological framework was quantitative, and the Mann-Whitney U test was used in order to make comparisons between groups (with/without stakeholder management). Findings: As a result, there is the empirical evidence of stakeholder management in the discussion of value creation and organizational performance. Research implications: This study advances in the empirical discussion of the relationship between stakeholders and the company in the orientation of value creation, since it provides statistical evidence that the stakeholder management has influence on the performance of companies. Research limitations: As a limitation, the study has the composition of the sectors, which can be expanded in future research, for all sectors of the BM&F Bovespa, including the 362 companies. A sample with several sectors can improve the inferences. Practical implications: The study improves the understanding that it is not the fact that it belongs to the index, as it is the case of ISE-GRI, that the company's results point to a superior performance of those that do not belong, but the effective management of stakeholders for a positive result in the short and long term, as it was evidenced in this study. Originality/value: It also demonstrates the empirical evidence of issues, until then dealt with in the theoretical field, but with no direct relationship with a set of companies, as well as supporting the idea that the creation of connections between companies and stakeholders open invisible opportunities for value creation.Objetivo: O objetivo desta pesquisa é evidenciar, empiricamente, a gestão de stakeholders nos indicadores de desempenho das empresas de capital aberto. Metodologia: A partir de um enquadramento metodológico quantitativo, foi utilizado o teste Mann-Whitney U para realizar as comparações entre os grupos (com/sem gestão de stakeholders). Resultados: Como resultado, tem-se a evidência estatística empírica da gestão de stakeholders na discussão da criação de valor e desempenho organizacional. Implicações práticas: O estudo melhora o entendimento de que não é o fato de pertencer ao índice, como é o caso do ISE-GRI, que os resultados da empresa apontam desempenho superior das que não pertencem, mas sim da gestão efetiva de stakeholders para um resultado positivo a curto e em longo prazo, como foi evidenciado neste estudo. Limitação: Como limitação o estudo tem a composição dos setores, que pode ser ampliado em pesquisas futuras, para todos os setores da BM&F Bovespa, incluindo as 362 empresas. Uma amostra com diversos setores pode melhorar as inferências. Originalidade:O estudo demonstra evidências empíricas de questões, até então tratadas no campo teórico, mas sem relação direta com um conjunto de empresas, bem como ampara a ideia de que a criação de conexões entre empresa e stakeholders abrem oportunidades invisíveis para a criação de valor

Anomalous diffusion on crumpled wires in two dimensions

It is investigated the statistical properties of random walks evolving on real configurations of a crumpled wire rigidly jammed in two dimensions. These crumpled hierarchical structures with complex topology are obtained from a metallic wire injected at a constant rate into a transparent planar cell of 20cm of diameter. The observed diffusion is anomalous with an exponent very close to that obtained at the threshold of two dimensional percolation. A comparison of the system studied in this paper with other systems of physical interest is also made, and an experimental consequence of our results is discussed.Comment: 10 pages including 4 figures. Physica A (2006). Preprin