Evaluating big science: CERN's past performance and future prospects

After explaining the reasons why science policy-makers face a growing need for more rigorous forms of research evaluation, we outline an approach combining bibliometric and peer-evaluation data that has been developed at the Science Policy Research Unit in the course of a programme of studies of Big Science specialties. The paper describes the results obtained when this method of converging partial indicators is applied to compared the past research performance of the accelerators at CERN — the joint European Laboratory for Particle Physics — with that of the world's other main accelerators. The paper concludes by demonstrating how, on the basis of an analysis of the factors that have structured research performance in the past, it is possible to arrive at a systematic set of conclusions about the future prospects for a major new research facility such as an accelerator.No order of seniority implied (rotating first authorship). The authors are Fellows of the Science Policy Research Unit (SPRU), University of Sussex, where they work on a range of issues connected with policies for basic and applied research. They gratefully acknowledge the support of the British Economic and Social Research Council in carrying out this research, and that of the Leverhulme Trust in meeting the costs of additional analysis and the writing of this paper. The autors also wish to thank various colleagues at SPRU, especially Professors LindaWilson and KeithPavitt, for numerous useful comments and criticisms. An earlier version of the paper was presented at an Imperial College/Science Policy Research Unit seminar in May 1983, and at a Nordic Scientific Policy Council conference held in Helsinki during February 1984.     

Bioinspired Viscoelastic Capsules: Delivery Vehicles and Beyond

Microcapsules are often used as individually dispersed carriers of active ingredients to prolong their shelf life or to protect premature reactions with substances contained in the surrounding. This study goes beyond this application and employs microcapsules as principal building blocks of macroscopic 3D materials with well‐defined granular structures. To achieve this goal and inspired by nature, capsules are fabricated from block‐copolymer surfactants that are functionalized with catechols, a metal‐coordinating motive. These surfactants self‐assemble at the surface of emulsion drops where they are ionically cross‐linked to form viscoelastic capsules that display a low permeability even toward small encapsulants. It is demonstrated that the combination of the mechanical strength, flexibility, and stickiness of the capsules enables their additive manufacturing into macroscopic granular structures. Thereby, they open up new opportunities for 3D printing of soft, self‐healing materials composed of individual compartments that can be functionalized with different types of spatially separated reagents.     

The influence of settling time on the formation of aerobic granules.

Aerobic granular sludge, without the addition of carrier material, has only been reported in one suspended growth system, the Sequencing Batch Reactor (SBR) operated with short fill and settling periods. Recent studies have demonstrated that extracellular polysaccharides increased with the formation of aerobic granules, and that the shear force may stimulate production of these polysaccharides. In the study described herein, two SBRs were operated with the same shear force (air flow rate 275 L h(-1)) and two different settling times (2 and 10 min). Only the reactor with 2 min settling formed completely granular sludge, although granules were present in both reactors. Community analysis using 16S rRNA PCR products and DGGE showed that the communities diverged quickly after reactor start-up. For samples taken at steady-state, the granular population was more stable and less diverse than the flocculent reactor. EPS extraction of samples using cation exchange resin yielded similar values for aerobic granular sludge and previously reported anaerobic granules. While differences in the protein and TOC content between the flocculent and granular reactors increased appreciably as the sludge became more granular, the protein to polysaccharide ratio was relatively constant. The experiment confirmed previous theories that short settling times in SBRs select for granular sludge. The settling time results in granular sludge having a higher EPS protein content and a less diverse but more stable population.     

General Image-Quality Equation: GIQE

A regression-based model was developed relating aerial image quality, expressed in terms of the National Imagery Interpretability Rating Scale (NIIRS), to fundamental image attributes. The General Image-Quality Equation (GIQE) treats three main attributes: scale, expressed as the ground-sampled distance; sharpness, measured from the system modulation transfer function; and the signal-to-noise ratio. The GIQE can be applied to any visible sensor and predicts NIIRS ratings with a standard error of 0.3 NIIRS. The image attributes treated by the GIQE are influenced by system design and operation parameters. The GIQE allows system designers and operators to perform trade-offs for the optimization of image quality.     

Sinterability of commercial 8 mol% yttria-stabilized zirconia powders and the effect of sintered density on the ionic conductivity

The sintering behaviour of a number of commercially produced 8 mol% yttria-stabilized zirconia powders has been studied. The effect of different sintering regimes on the density and microstructure of the sintered ceramic was determined using density measurements, scanning electron microscopy (SEM) and dilatometry. The chemical homogeneity, particle size and the morphology of the as-received powder were related to the sintering behaviour of the different commercial powders. Powders prepared via a route which involved a spray-drying step sintered more readily than those prepared without a spray-drying step. Plasma-derived powders did not sinter to as high an apparent density as co-precipitated powders. The effect of sample density on the ionic conductivity of sintered YSZ ceramics was studied using a.c. impedance spectroscopy. This technique allowed separation of the bulk and grain-boundary components, enabling clear intepretation of the effects of sample porosity of the conduction pathways. Ceramics prepared from the three different powders achieved a bulk ionic conductivity of 16 S cm-1 at 1000 °C for sintered densities of 95% or greater. The results obtained are compared to values reported for a variety of other commercial powders. © 1998 Kluwer Academic Publishers     

Homogeneous Doping of Substitutional Nitrogen/Carbon in TiO2 Plates for Visible Light Photocatalytic Water Oxidation

Extending the light absorption range of wide‐bandgap photocatalysts into the visible light region is significant in terms of fully harvesting and converting solar light. The desirable band‐to‐band redshift of the absorption edge of semiconducting binary metal oxides such as prototypical photocatalyst TiO₂ by doping is long targeted but remains a challenge, up to date. Here, by taking the advantage of abundant 1D diffusion channels with rhombus‐like cross‐sections along the c‐axis in the crystal structure of titanium oxalate hydrate to promote the entrance of nitrogen dopant species into the bulk and subsequent thermal topotactic transition in an atmosphere of gaseous ammonia, homogeneous doping of substitutional carbon/nitrogen for oxygen in the TiO₂ decahedral plates with a dominant anatase phase is obtained for the first time. The resultant TiO_2?x(CN)_y with an unusual band‐to‐band visible light absorption spectrum can induce photocatalytic water oxidation to release oxygen under visible light irradiation. This study provides not only a promising visible light–responsive TiO₂ photocatalyst, but also an important strategy for developing other solar‐driven photocatalysts.     

Composite Dissolving Microneedles for Coordinated Control of Antigen and Adjuvant Delivery Kinetics in Transcutaneous Vaccination

Transcutaneous administration has the potential to improve therapeutics delivery, providing an approach that is safer and more convenient than traditional alternatives, while offering the opportunity for improved therapeutic efficacy through sustained/controlled drug release. To this end, a microneedle materials platform is demonstrated for rapid implantation of controlled‐release polymer depots into the cutaneous tissue. Arrays of microneedles composed of drug‐loaded poly(lactide‐co‐glycolide) (PLGA) microparticles or solid PLGA tips are prepared with a supporting and rapidly water‐soluble poly(acrylic acid) (PAA) matrix. Upon application of microneedle patches to the skin of mice, the microneedles perforate the stratum corneum and epidermis. Penetration of the outer skin layers is followed by rapid dissolution of the PAA binder on contact with the interstitial fluid of the epidermis, implanting the microparticles or solid polymer microneedles in the tissue, which are retained following patch removal. These polymer depots remain in the skin for weeks following application and sustain the release of encapsulated cargos for systemic delivery. To show the utility of this approach the ability of these composite microneedle arrays to deliver a subunit vaccine formulation is demonstrated. In comparison to traditional needle‐based vaccination, microneedle delivery gives improved cellular immunity and equivalent generation of serum antibodies, suggesting the potential of this approach for vaccine delivery. However, the flexibility of this system should allow for improved therapeutic delivery in a variety of diverse contexts.     

Nitrogen retention in a river system and the effects of river morphology and lakes.

The mean annual transfer (loss and retention) of nitrogen in a river system was estimated using a conceptual approach based on water surface area and runoff. Two different approaches for the calculation of water surface area were applied to determine riverine nitrogen retention in four European catchments, ranging between 860-14,000 km2 in area, and differing considerably in the proportion and distribution of surface waters, specific runoff and specific nutrient emissions. The transfer rate was estimated sequentially as either the mean value for the total catchment, on a sub-catchment scale, or considering the distribution of water surface area within a sub-catchment. For the latter measure, nitrogen retention in larger lakes was calculated separately. Nitrogen emissions modelled with MONERIS and HBV-N were used to calculate nitrogen river loads and compare those with observed loads. Inclusion of the proportion of water area within a sub-catchment improved modelled results in catchment with large lakes in sub-catchments, but not where there was a homogenous distribution of surface waters among sub-catchments.