Nanoscale roughness and morphology affect the IsoElectric Point of titania surfaces

We report on the systematic investigation of the role of surface nanoscale roughness and morphology on the charging behaviour of nanostructured titania (TiO2) surfaces in aqueous solutions. IsoElectric Points (IEPs) of surfaces have been characterized by direct measurement of the electrostatic double layer interactions between titania surfaces and the micrometer-sized spherical silica probe of an atomic force microscope in NaCl aqueous electrolyte. The use of a colloidal probe provides well-defined interaction geometry and allows effectively probing the overall effect of nanoscale morphology. By using supersonic cluster beam deposition to fabricate nanostructured titania films, we achieved a quantitative control over the surface morphological parameters. We performed a systematical exploration of the electrical double layer properties in different interaction regimes characterized by different ratios of characteristic nanometric lengths of the system: the surface rms roughness Rq, the correlation length {\xi} and the Debye length {\lambda}D. We observed a remarkable reduction by several pH units of IEP on rough nanostructured surfaces, with respect to flat crystalline rutile TiO2. In order to explain the observed behavior of IEP, we consider the roughness-induced self-overlap of the electrical double layers as a potential source of deviation from the trend expected for flat surfaces.Comment: 63 pages, including 7 figures and Supporting Informatio

Exact numerical diagonalization of one-dimensional interacting electrons nonadiabatically coupled to phonons

We study the role of non-adiabatic Holstein electron-phonon coupling on the neutral-ionic phase transition of charge transfer crystals which can be tuned from continuous to discontinuous, using exact numerical diagonalization. The variation of electronic properties through the transition is smoothed by nonadiabaticity. Lattice properties are strongly affected, and we observe both squeezing and antisqueezing, depending on details of the adiabatic potentials, and identify the quantum uncertainty of the phonons as the most sensitive measure of nonadiabaticity. The adiabatic limit is regular for a continuous transition but turns out completely inadequate near a discontinuous transition. The relevance of coherent state approaches is assessed critically.Comment: latex manuscript (7 pages), 3 eps figures; revised version, better discussion, one figure replaced; to be published in Europhys. Let

Hybrid Pixel Detector Development for the Linear Collider Vertex Tracker

In order to fully exploit the physics potential of the future high energy e+e- linear collider, a Vertex Tracker able to provide particle track extrapolation with very high resolution is needed. Hybrid Si pixel sensors are an attractive technology due to their fast read-out capabilities and radiation hardness. A novel pixel detector layout with interleaved cells has been developed to improve the single point resolution. Results of the characterisation of the first processed prototypes by electrostatic measurements and charge collection studies are discussed.Comment: 5 pages, 1 figure, to appear in the Proceedings of the 9th Int. Workshop on Vertex Detectors, Lake Michigan MI (USA), September~200

Hybrid areas of work between employment and self-employment : emerging challenges and future research directions

The growth of non-standard employment relations has created one of the major challenges in terms of workers\u2019 rights as well as collective representation in European societies. Among non-standard employment relations, so-called \u201csolo self-employed\u201d\u2014self-employed workers without employees\u2014are challenging the very foundations of our labor markets, that is to say the opposition between employers and employees, fostering the development of emerging \u201chybrid\u201d areas of work. The heterogeneity of the solo self-employed is difficult to capture from official statistics, which are still based on traditional classifications, and questions also the legal categories that qualify these workers. Moreover, the fact that solo self-employed workers do not form a homogenous group, and are diverse in terms of their activities, interests and needs, calls for changes in the way trade unions, employer organizations, and new freelancer associations develop collective actions, claims-making activities, and strategies of organizing. With the aim to achieve an in-depth understanding of the increasingly extensive and populated categories of the solo self-employed, this contribution aims at reconstructing the state of the art within different fields of study, such as employment relations, labor law, industrial relations and social movements, and at offering some possible future research directions

A Pixel Vertex Tracker for the TESLA Detector

In order to fully exploit the physics potential of a e+e- linear collider, such as TESLA, a Vertex Tracker providing high resolution track reconstruction is required. Hybrid Silicon pixel sensors are an attractive sensor technology option due to their read-out speed and radiation hardness, favoured in the high rate TESLA environment, but have been so far limited by the achievable single point space resolution. A novel layout of pixel detectors with interleaved cells to improve their spatial resolution is introduced and the results of the characterisation of a first set of test structures are discussed. In this note, a conceptual design of the TESLA Vertex Tracker, based on hybrid pixel sensors is presentedComment: 20 pages, 11 figure

The impact of service robots on customer satisfaction online ratings: The moderating effects of rapport and contextual review factors

Recent research has established a positive relationship between the use of service robots powered by artificial intelligence in hospitality firms and customer satisfaction online ratings, a particularly important form of electronic word of mouth. However, it is not clear if and how this relationship is augmented or diminished by moderating factors. In this study, we examined four potential moderators by using machine learning and natural language processing techniques to analyze 20,166 online reviews of hotels that had implemented service robots. We had four key findings. First, a positive service robot-satisfaction rating relationship was further enhanced by improved customer-service robot rapport during the service encounter. Second, higher customer effort focused on service robots in a review reduced the service robot-satisfaction rating relationship. Third, posting reviews using a mobile device (vs. other devices) showed higher satisfaction ratings. Finally, customers' prior experience in writing online reviews was unrelated to the service robot-satisfaction rating relationship. Taken together, these results suggest that service robots should be designed to be interactive and encourage customers to build rapport, for example, by service robots engaging in conversational flows. Moreover, customers should be nudged to use their mobile devices to post timely reviews on their positive human–robot interactions