Kings in the Direct Product of Digraphs

A k-king in a digraph D is a vertex that can reach every other vertex in D by a directed path of length at most k. A king is a vertex that is a k-king for some k. We will look at kings in the direct product of digraphs and characterize a relationship between kings in the product and kings in the factors. This is a continuation of a project in which a similar characterization is found for the cartesian product of digraphs, the strong product of digraphs, and the lexicographic product of digraphs

Ab initio group model potentials including electron correlation effects

A method for determination of ab initio group model potentials, with the intention of describing the effects of a whole molecule or a chemical group within a density functional theory framework, is reported. The one-electron part of the Kohn–Sham equations is modified by incorporation of a Coulomb operator, which accounts for the classical electron interaction arising from the group. Exchange and correlation effects are introduced by a suitable modification of the exchange-correlation functionals. The strong orthogonality condition, usually required by the theory of separability of many electron systems, is written in terms of first order reduced density matrices. In order to check the method a group model potential for H2O (environment) was obtained and employed in the calculation of HF⋯H2O and H2O⋯H2O complexes using several functionals. Equilibrium intergroup distances and binding energies are compared with all-electron calculations.Dirección General de Enseñanza Superior (DGES). España PB98-1125Junta de Andalucía FQM13

Mechanism of Cu deposition on the α−Al2O3 (0001) surface

The growth mechanism of the Cu/α−Al2O3 (0001) interface is studied by first-principles molecular-dynamics simulations as a function of the transition-metal coverage (θ) and the temperature of the system. On the anhydrous surface growth of Cu(0) 3D clusters is predicted. On the partially hydroxylated surface, a Cu(I) monolayer, relatively stable upon the temperature rising, is first observed (θ<1/3  ML). Increasing Cu loading leads to Cu(I)/Cu(0) mixed phases that when heated aggregate into 3D particles increasing the number of Cu(0) atoms, in agreement with the Auger spectra of Kelber et al.Ministerio de Ciencia y Tecnología MAT2002-057

Electronic structure of porphyrin-based metal– organic frameworks and their suitability for solar fuel production photocatalysis

Metal–organic frameworks (MOFs) can be exceptionally good catalytic materials thanks to the presence of active metal centres and a porous structure that is advantageous for molecular adsorption and confinement. We present here a first-principles investigation of the electronic structure of a family of MOFs based on porphyrins connected through phenyl-carboxyl ligands and AlOH species, in order to assess their suitability for the photocatalysis of fuel production reactions using sunlight. We consider structures with protonated porphyrins and those with the protons exchanged with late 3d metal cations (Fe2+, Co2+, Ni2+, Cu2+, Zn2+), a process that we find to be thermodynamically favorable from aqueous solution for all these metals. Our band structure calculations, based on an accurate screened hybrid functional, reveal that the bandgaps are in a favorable range (2.0 to 2.6 eV) for efficient adsorption of solar light. Furthermore, by approximating the vacuum level to the pore centre potential, we provide the alignment of the MOFs' band edges with the redox potentials for water splitting and carbon dioxide reduction, and show that the structures studied here have band edges positions suitable for these reactions at neutral pH.Royal Society for an International Exchange Scheme grantVia our membership of the UK's HPC Materials Chemistry Consortium, which is funded by EPSRC (EP/L000202), this work made use of the facilities of ARCHER, the UK's national high-performance computing services, which are funded by the Office of Science and Technology through EPSRC's High End Computing ProgrammeEuropean Research Council through an ERC Starting Grant (ERC2011-StG-279520-RASPA)MINECO (CTQ2013-48396-P)Andalucía Region (FQM-1851)University of Granad

Governance of substance use as a by-product of policing in Norway : a historical account

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Effect of on-site Coulomb repulsion term U on the band-gap states of the reduced rutile (110) TiO2 surface

We present a study concerning the effect of the on site d-d Coulomb interaction energy U on the band-gap states of nonstoichiometric rutile 110 TiO2 surface. As well known, the excess electrons resulting from the formation of oxygen vacancies localize on the Ti 3d orbitals forming band-gap states. Local density approximation LDA does not give a correct description of these band-gap states, either with or without gradient corrections. The failure of LDA is often attributed to an inadequate treatment of electron correlation in systems with localized orbitals and is commonly corrected with an empirical local Coulomb repulsion term, i.e., the LDA+U method. This study provides a completely general strategy to estimate the U value in this kind of systems, illustrated here for reduced 110 TiO2 surface, well characterized from experiments. From ab initio embedded cluster configuration interaction calculations, combined with the effective Hamiltonian theory, a value of U of 5.5±0.5 eV is obtained, in good agreement with those reported for this system from x-ray photoemission spectroscopy experiments U=4.5±0.5 eV . It is observed that when the ab initio estimate of U is injected into the periodic LDA+U calculations, a correct description of the gap states is obtained from the periodic LDA+U calculations. Additionally, the results indicate that the position of these states on the band gap strongly depends on the level at which lattice relaxation is taken into account, with significant differences between the density of states curves at the LDA+U level obtained using the optimal generalized gradient approximation or LDA+U geometries. These results suggest that this combined strategy could be a useful tool for those systems where electron correlation plays a key role, and no experimental data are available for the on-site Coulomb repulsio

Goodbye to Projects? ¿ A livelihoods-grounded audit of the Magu District Livelihoods and Food Security Project (MDLFSP) in Tanzania

Approaches to projects and development have undergone considerable change in the last decade with significant policy shifts on governance, gender, poverty eradication, and environmental issues. Most recently this has led to the adoption and promotion of the sustainable livelihood (SL) approach. The adoption of the SL approach presents challenges to development interventions including: the future of projects and programmes, and sector wide approaches (SWAPs) and direct budgetary support. This paper `A livelihoods-grounded audit of the Magu District Livelihoods and Food Security Project¿ is the ninth in the series of project working papers.Department for International Developmen

Gravpælen på Moesgaard: Om indsamlingen af en fototra i Anororo (Madagaskar)

Hvordan indsamles en etnografisk genstand i dag? Nærværende artikel er en feltberetning om, hvordan idéentil at indsamle en gravpæl på Madagaskar opstod og gennem en lang række forhandlinger lod sig realisere.Med afsæt i et gravpælsritual i en sihanakansk dødeby ved landsbyen Anororo, tages læseren med til undfangelsenaf idéen om det tilsyneladende uladsiggørlige projekt. Vi følger forhandlingerne med landsbyboerne, udvælgelsenog fældningen af et gaffelformet træ, fremstillingsprocessen og endelig den lange rejse op gennem højlandet, ud til en havneby og med skib tusindvis af kilometer nordpå til Aarhus

The consumer empowerment index. A measure of skills, awareness and engagement of European consumers

The Consumer Empowerment Index is a pilot exercise, aimed at obtaining a first snapshot of the state of consumer empowerment as measured by the Eurobarometer survey (Special Eurobarometer n. 342). It is neither a final answer on empowerment nor a comprehensive study on all the different facets of consumer empowerment, but instead it is meant to foster the debate on the determinants of empowerment and their importance for protecting consumers. This report describes the steps followed in the construction of the Index of consumer Empowerment. In particular the definition of the theoretical framework, the quantification of categorical survey questions, the univariate and multivariate analysis of the dataset, and the set of weight used for calculating the scores and ranks of the Index. The report also discusses the robustness of the results and the relationship between the Index and the socio-economic characteristics of the respondents in order to identify the features of the most vulnerable consumers. The Consumer Empowerment Index identifies Norway as the leading country followed by Finland, the Netherlands and Germany and Denmark. The middle of the ranking is dominated by western countries such as Belgium, France, and UK, with an average score 13% lower than the top five. At the bottom of the Index are some Eastern and Baltic countries like Bulgaria, Lithuania, Poland, and Romania with a score 31% lower on average (this gap reaches 40% and 38% in Awareness of consumer legislation and Consumer skills). A group of southern countries, Italy, Portugal, and Spain score poorly in the Index, especially in the pillar Consumer skills where the gap with the top performers reaches 30%.Consumer empowerment; composite indicators