iCrawl: Improving the Freshness of Web Collections by Integrating Social Web and Focused Web Crawling

Researchers in the Digital Humanities and journalists need to monitor, collect and analyze fresh online content regarding current events such as the Ebola outbreak or the Ukraine crisis on demand. However, existing focused crawling approaches only consider topical aspects while ignoring temporal aspects and therefore cannot achieve thematically coherent and fresh Web collections. Especially Social Media provide a rich source of fresh content, which is not used by state-of-the-art focused crawlers. In this paper we address the issues of enabling the collection of fresh and relevant Web and Social Web content for a topic of interest through seamless integration of Web and Social Media in a novel integrated focused crawler. The crawler collects Web and Social Media content in a single system and exploits the stream of fresh Social Media content for guiding the crawler.Comment: Published in the Proceedings of the 15th ACM/IEEE-CS Joint Conference on Digital Libraries 201

The Electronic Structure of Vanadium Oxides as Catalysts in the Selective Oxidation of Small Alkanes

The present work considers vanadium oxides catalysts in the selective oxidation of small alkanes. The dynamics of their (surface) electronic structure modulated by the chemical potential of reaction gases were investigated regarding charge carrier dynamics, surface valence/conduction band structure and work function modifications. The charge carrier dynamics were studied with the in situ microwave cavity perturbation technique allowing the determination of the catalyst conductivity in a contact free manner in a fixed bed reactor geometry. An evaluation program based on the transmission line theory was developed for precise conductivity determination. The validity of the evaluation methods was tested with the n-type semiconducting vanadium pentoxide in the oxidation of n-butane. In agreement with literature, the experiments revealed an n-type conductivity. The addition of n-butane in the reaction feed leads to an increased conductivity corresponding to the abundance of electronically active V4+ defect states (corresponding to oxygen vacancies) in the forbidden bandgap of vanadium pentoxide increasing the mobile electron density. Based on results of the reference study, the selective propane oxidation catalyst MoVNbTeO x M1-phase was investigated in the selective oxidation of ethane, propane and n-butane. Also the impact of water in the propane feed, triggering the abundance of the industrially important key product acrylic acid, on the MoVNbTeOx M1-phase electronic structure was studied. The in situ microwave cavity perturbation studies at ambient pressure were complemented with near ambient pressure X-ray photoelectron and X-ray absorption spectroscopy investigations at 0.25 mbar to understand the charge transfer processes according to semiconductor physics. The conductivity of MoVNbTeOx M1-phase increased with increasing propane to oxygen ratio identifying MoVNbTeOx M1-phase as an n-type semiconductor. In the alkane (ethane, propane and n-butane) exchange experiment, the number of electrons transferred to MoVNbTeOx M1-phase increased from ethane, to propane and finally to n-butane oxidation resulting in an increased conductivity. The X-ray photoelectron spectroscopy reveals that the exchange of the alkane leads to a modulation of the V4+/V5+ redox couple at the surface corresponding to shifts of the valence band edge and electron affinity. Thus the surface of MoVNbTeOx M1-phase, being in dynamic equilibrium with the bulk electronic structure, is modified by the compositions (corresponding to the chemical potential) of the gas phase. The bulk charge carrier density is triggered by the barrier height of the surface induced space charge layer resulting in a modified conductivity. In contrast the modulated electron affinity can be explained by a change of the surface dipole. Water in propane feed leads to a decreased conductivity of MoVNbTeOx M1-phase without a modification of the space charge layer. A drastic change of the surface elemental composition, in particular the abundance of V5+ , is induced by water, observable in the valence band, core level and vanadium L2,3-edges X-ray absorption spectra. The surface modifications were accompanied with a decreased electron affinity corresponding to a decreased surface dipole. The drastically changed valence and conduction band structure likely affects the charge carrier mobility explaining the decreased conductivity in steam containing propane feed. However, results from low pressure in situ photoelectron studies are debated according to their relevance for "real" catalysis at ambient pressures. In particular the oxygen pressure controls the oxidation state of transition metal oxide surfaces. The vanadium L2,3 X-ray absorption edges of vanadyl pyrophosphate were investigated in the selective n-butane oxidation at 10, 100 and 1000 mbar to identify a possible pressure gap using the surface sensitive conversion electron mode. As a result, at low pressures the oxidation of the surface is controlled by the oxygen pressure. In contrast at higher pressures, the surface state of oxidation is triggered by the catalytic reaction providing a steady state between reduction of the catalyst during n-butane conversion and re-oxidation by molecular oxygen

CO adsorption on the surface of MgO(001) thin films

We report infrared reflection–absorption and thermal desorption spectra of CO adsorbed at low temperature (30 K) on the surface of MgO(001) thin films. The high similarity of the observed IR bands as compared to data reported for MgO(100) single crystals and sintered MgO particles gives evidence for the identical surface morphology of the different substrates. CO adsorption series taken at constant temperature/variable pressure, variable temperature/constant pressure, as well as isotope mixing experiments reveal almost no diffusion of CO on MgO(001) at low temperature, but high adsorbate mobility at slightly elevated temperature

The significance of financial self efficacy in explaining women's personal finance behaviour

Much policy attention has been placed on enhancing individuals' financial knowledge and literacy, chiefly through financial education programs. However, managing one's personal finances takes more than financial knowledge and literacy: an individual also needs a sense of self-assuredness, or 'self-belief', in their own capabilities. This personal attribute is known within the psychology literature as 'self-efficacy'. This paper examines the significance of an individual's financial self-efficacy in explaining their personal finance behaviour, through the application of a psychometric instrument. Using a 2013 survey of Australian women, financial self-efficacy emerges as one of the strongest predictors of the type and number of financial products that a woman holds. Specifically, our analysis reveals that women with higher financial self-efficacy - that is, with greater self-assuredness in their financial management capacities - are more likely to hold investment and savings products, and less likely to hold debt-related products. Even alongside other important factors - such as education, financial risk preferences, age and household income - the explanatory power of financial self-efficacy is found to be significant at the 1% critical level. Moreover, the significance of financial self-efficacy is independently identified from that of financial literacy factors, which bears important implications for the development of policies aiming to improve financial outcomes

catalysis

The development of model catalyst systems for heterogeneous catalysis going beyond the metal single crystal approach, including phenomena involving the limited size of metal nanoparticles supported on oxide surfaces, as well as the electronic interaction through the oxide–metal interface, is exemplified on the basis of two case studies from the laboratory of the authors. In the first case study the reactivity of supported Pd nanoparticles is studied in comparison with Pd single crystals. The influence of carbon contaminants on the hydrogenation reaction of unsaturated hydrocarbons is discussed. Carbon contaminants are identified as a key parameter in those reactions as they control the surface and sub-surface concentration of hydrogen on and in the particles. In the second case study, scanning probe techniques are used to determine electronic and structural properties of supported Au particles as a function of the number of Au atoms in the particle. It is demonstrated how charge transfer between the support and the particle determines the shape of nanoparticles and a concept is developed that uses charge transfer control through dopants in the support to understand and design catalytically active materials

The politics of international redistribution: Explaining public support for fiscal transfers in the EU

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.As a consequence of the Eurozone crisis and the creation of the European Stability Mechanism (ESM), the prospect of a transfer union has become a particularly contested aspect of European integration. How should one understand the public backlash against fiscal transfers? And, what explains voter preferences for international transfers more generally? Using data from the 2014 European Elections Study (EES), this article describes the first cross-national analysis of voters’ preferences on international transfers. The analysis reveals a strong association between voters’ non-economic cultural orientations (i.e., their cosmopolitanism) and their position on transfers. At the same time, it is found that voters’ economic left-right orientations are crucial for a fuller understanding of the public conflict over transfers. This counters previous research that finds economic left-right orientations to be of little explanatory value. This study demonstrates that the association between economic left-right orientations and preferences for international transfers is conditional on a person's social class. Among citizens in a high-income class an economically left-leaning position is associated with support for transfers, whereas it is associated with opposition to transfers among citizens in a low-income class