In Search of Concerted Strategies for Competitive and Resilient Regions

The European space-economy represents a complex system with a great internal heterogeneity, intensive socioeconomic interactions and differential growth trajectories among countries and regions. The present study aims to investigate the connectivity between spatial competitiveness and resilience in Europe and seeks to design an operational framework for concerted strategies of competitive and resilient regions. To assess the linkage between resilience and competitiveness, we have developed a new measure, viz. the Resilience and Competitiveness Index (RACI) as a function of two constituent sub-indices: Resilience and Competitiveness. This approach is tested on the basis of detailed data on European regions. The empirical results from 268 EU NUTS2 regions offer a solid anchor point for the proposed operational framework for concerted development strategies of competitive and resilient regions. Our research distinguishes and proposes several systematic types of concerted regional strategies according to the performance of a region measured by Resilience and Competiveness sub-indices. A key result of the study is the design of an operational constellation for strategic regional policy evaluation, with a major added value for policy- and decision-making purposes. The use of official data from Eurostat and of standard indicators in our research assures continuity and consistency with the official Regional Competitiveness Index (RCI) classification and measurement, so that policy makers are able to compare the performance of their regions over time and to develop proper concerted strategies accordingly. The clear evidence of a connectivity between regional competitiveness and resilience may help to develop a governance approach that balances competitiveness (mainly represented by productive assets) with resilience (mainly represented by sustainability and ecological awareness) and thus to deal with the complexity in socioeconomic systems.

     

Farm-scale bio-power-to-methane: Comparative analyses of economic and environmental feasibility

Power-to-gas technologies are considered to be part of the future energy system, but their viability and applicability need to be assessed. Therefore, models for the viability of farm-scale bio-power-to-methane supply chains to produce green gas were analysed in terms of levelised cost of energy, energy efficiency and saving of greenhouse gas emission. In bio-power-to-methane, hydrogen from electrolysis driven by surplus renewable electricity and carbon dioxide from biogas are converted to methane by microbes in an ex situ trickle-bed reactor. Such bio-methanation could replace the current upgrading of biogas to green gas with membrane technology. Four scenarios were compared: a reference scenario without bio-methanation (A), bio-methanation (B), bio-methanation combined with membrane upgrading (C) and the latter with use of renewable energy only (all-green; D). The reference scenario (A) has the lowest costs for green gas production, but the bio-methanation scenarios (B-D) have higher energy efficiencies and environmental benefits. The higher costs of the bio-methanation scenarios are largely due to electrolysis, whereas the environmental benefits are due to the use of renewable electricity. Only the all-green scenario (D) meets the 2026 EU goal of 80% reduction of greenhouse gas emissions, but it would require a CO₂ price of 200 € t⁻¹ to achieve the levelised cost of energy of 65 €ct Nm⁻³ of the reference scenario. Inclusion of the intermittency of renewable energy in the scenarios substantially increases the costs. Further greening of the bio-methanation supply chain and how intermittency is best taken into account need further investigation.     

Magnetic field spatial Fourier analysis: A new opportunity for high resolution current localization

Magnetic microscopy has proven its usefulness throughout the years. It allows current localization with a certain degree of precision by using an inversion algorithm to invert the Biot–Savart law. The goal is to obtain the current distribution once the magnetic field is given. However, in order to obtain a stable solution, the magnetic data is severely low-pass filtered in the spatial Fourier domain, and some important information is lost. In this paper, the contribution given by the different spatial frequencies was studied: it was demonstrated how this information can be used to obtain additional information regarding the position of the currents. A comparative study between the theoretical approach and the application to the measurements is also shown.     

The effect of Cd and vitamin D3 on the solidity of eggshell

 The effect of cadmium and vitamin D₃ on the solidity of eggshells was observed. Laying hens were divided into 7 groups with 10 animals per group. In the experimental groups 1, 2, and 3, we administered daily 0.3; 10.0, and 15.0 mg CdCl₂ kg^–1 body weight, respectively; in experimental groups 4, 5, and 6 were administered the same CdCl₂ concentrations as above supplemented with a preventive dose of vitamin D₃ Group 7 was the control group. In groups 1, 2, and 3, the mean values of solidity were 29.50; 27.58, and 27.34 N/cm². In the control group, the mean value was 34.05 N/cm². In the experimental groups 4, 5, and 6, supplemented with vitamin D₃ and cadmium, the values were significantly higher: 34.26, 30.59, and 29.48 N/cm², respectively It is obvious that the interaction of vitamin D₃ with Cd reduced an adverse effect of cadmium. Received: 14 February 2000 / Revised version: 15 May 2000     

Structural analysis of an InGaN/GaN based light emitting diode by X-ray diffraction

The important structural characteristics of hexagonal GaN in an InGaN/GaN multi quantum well, which was aimed to make a light emitted diode and was grown by metalorganic chemical vapor deposition on c-plain sapphire, are determined by using nondestructive high-resolution X-ray diffraction in detail. The distorted GaN layers were described as mosaic crystals characterized by vertical and lateral coherence lengths, a mean tilt, twist, screw and edge type threading dislocation densities. The rocking curves of symmetric (00.l) reflections were used to determine the tilt angle, while the twist angle was an extrapolated grown ω-scan for an asymmetric (hk.l) Bragg reflection with an h or k nonzero. Moreover, it is an important result that the mosaic structure was analyzed from a different (10.l) crystal direction that was the angular inclined plane to the z-axis. The mosaic structure parameters were obtained in an approximately defined ratio depending on the inclination or polar angle of the sample.     

Surface science approach to the preparation and characterization of model Ziegler–Natta heterogeneous polymerization catalysts

Ziegler–Natta heterogeneous catalytic systems are extensively used to polymerize ethylene and propylene. Some industrial catalysts consist of TiCl₄ chemisorbed on activated MgCl₂ and subsequently reduced and alkylated by reaction with an aluminum alkyl (generally AlEt₃). Lewis bases are added to the catalytic systems to control the enantio-selectivity for the production of isotactic polypropylene. Our aim is to clarify the chemical composition of the active centers by modern surface science methods. Model catalysts are prepared in the form of ultra-thin films by gas-phase deposition on a gold foil in ultrahigh vacuum. Under these conditions, MgCl₂ films grow to controlled thickness via a layer-by-layer mechanism, as revealed by AES and XPS. TiCl₄ can be deposited on these films near room temperature by both electron irradiation-induced and metallic magnesium-induced chemical vapor deposition. Angle-resolved XPS studies indicate that these films consist of a few layers of TiCl₂ with one monolayer of TiCl₄ chemisorbed on its surface. The exposure of these titanium chloride films to the co-catalyst AlEt₃ produces an active model Ziegler–Natta catalyst. XPS analysis reveals the presence of TiCl₂Et on the catalyst surface: this is believed to be the active site. Prolonged reaction with the co-catalyst reduces the titanium sites to TiClEt_n (n = 1 and/or 2). High molecular weight polyethylene and polypropylene are synthesized on these catalysts, as shown by Raman spectroscopy. Highly isotactic polypropylene is produced without need for stereo-regulating Lewis bases. This revised version was published online in June 2006 with corrections to the Cover Date.     

Site-directed mutagenesis and X-ray crystallography of two phospholipase A2 mutants: Y52F and Y73F

Tyr52 and Tyr73 are conserved amino acid residues throughoutall vertebrate phospholipases A₂. They are part of an extendedhydrogen bonding system that links the N-terminal -NH⁺₃ -groupto the catalytic residues His48 and Asp99. These tyrosines werereplaced by phenylalanines in a porcine pancreatic phospholipaseA₂ mutant, in which residues 62–66 had been deleted (62–66PLA₂).The mutations did not affect the catalytic properties of theenzyme, nor the folding kinetics. The stability against denaturatlonby guanidine hydrochloride was decreased, however. To analysehow the enzyme compensates for the loss of the tyrosine hydroxylgroup, the X-ray structures of the Y52F and AY73F mutants weredetermined. After crystallographic refinement the final crystallographicR-factors were 18.1% for the %Y52F mutant (data between 7 and2.3 Å resolution) and 19.1% for the Y73F mutant (databetween 7 and 2.4 Å resolution). No conformational changesoccurred in the mutants compared with the 62–66PLA₂, butan empty cavity formed at the site of the hydroxyl group ofthe former tyrosine. In both mutants the Asp99 side chain losesone of its hydrogen bonds and this might explain the observeddestabilization.