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Guest editorial : the uses and misuses of the evaluation of cities and capitals of culture
Get PDFEvaluation has become a central feature of policymaking, used and often misused to shape and influence policy goals, priorities and practices. In the case of cultural mega events such as the European Capital of Culture (ECoC) and the UK City of Culture (UKCoC), which are the focus of this special issue, evaluation is a significant mechanism to shape, justify and inform urban cultural policies. Since the publication of the Myerscough (1994) and Palmer and Palmer/Rae Associates (2004) reports, the reputation of the ECoC initiative has been consolidated as an effective catalyst and accelerator for culture-led urban regeneration. After the emergence of the ECoC, many other international and national City of Culture (CoC) initiatives were established across the globe, including the UKCoC. Many policymakers highlight the benefits outlined in evaluation studies at different stages, ranging from the participation in competitive bidding and the implementation of a programme of cultural activities to post-event and legacy actions
Selective oxidation of biomass-derived 5‑hydroxymethylfurfural catalyzed by an iron-grafted metal–organic framework with a sustainably sourced ligand
Get PDFThe efficient conversion of biomass-derived 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is a major challenge under base-free conditions with inexpensive catalysts. We report a precious-metal-free recyclable MOF-based catalyst (CAU-28), constructed from the FDC ligand, with grafted redox-active Fe sites. This enables the conversion of HMF to FDCA under solvothermal heating or microwave-assisted methods in base-free aqueous conditions. The optimized process achieves 100% HMF conversion producing FDCA at the gram scale with a 70–80% yield in 1 h. The turnover frequency (TOF) and cost-normalized TOF for the best catalyst are >800 h–1 and >1000 h–1 £–1, respectively, surpassing those of conventional catalysts and processes using precious elements or basic additives for HMF conversion. The economic viability and practical applicability of the process are further realized by utilizing the catalytically derived FDCA (without purification) for the successful construction of pristine CAU-28 MOFs and formation of the biodegradable plastic polyethylene furanoate (PEF) after purification
Impact of discontinuous grain size distributions on the spectral energy distribution of debris disks
Get PDFContext. The collisional evolution of debris disks is expected to cause the characteristic wavy pattern, that is, an under- or overabundance of particles of specific sizes, of grain size distributions. This perturbed grain size distribution potentially leaves characteristic patterns in the spectral energy distribution (SED) of the disk system.
Aims. We aim to quantify and understand the specific influence of discontinuous particle size distributions on the appearance of debris disks. For this purpose, we considered dust emission models based on two different grain size distributions, namely, one with a single power law and one with a broken power law. In particular, our study is focused on the impact of an overabundance of small grains and an underabundance of medium-sized grains on the far-IR and (sub-)millimeter regime on the dust reemission radiation and the potential to constrain discontinuities in the grain size distribution from (sub-)millimeter photometric measurements of debris disks.
Methods. We compared the spectral index α (Fν ∝ να) in the case of a continuous grain size distribution with that of a discontinuous grain size distribution. We performed this comparison for central stars with different spectral types and two different disk structures (e.g., slim and broad debris dust rings).
Results. Within the considered parameter space, we found a characteristic difference between the spectral slopes of the SED in the different scenarios. In particular, the overabundance of small grains resulting from collisional events and thus parameters defining the outcome of disk events in debris disks is potentially observable by comparison with the SED corresponding to a grain size distribution resulting from an ideal collisional cascade. More specifically, the overabundance of small grains leads to a steeper slope in the far-IR and sub-millimeter regime, while the spectral index in the millimeter regime is hardly affected. On the other hand, the underabundance of medium-sized grains results in a slight steepening of the far-IR slope of the SED, but its primary effect is on the millimeter slope of the SED, causing it to become shallower. We also found that the impact of an overabundance of small dust particles is more pronounced than that of an underabundance of medium-sized dust particles. We also found that the difference between the spectral indices for the two different grain size distributions is largest for debris disks around brighter central stars and broader disks. However, the impact of the considered spatial distributions described by the fractional width of the disk system is weak. Our results also show that the dust composition is not the sole physical mechanism responsible for the spectral inversion observed in the far-IR to millimeter part of the SED of debris disk systems. Furthermore, the location of the spectral break is placed at different wavelength regimes if the grain size distribution is considered as a function of blowout size and stellar type
Functional closure properties of finite N-weighted automata
No full textWe determine all functional closure properties of finite N-weighted automata, even all multivariate ones, and in particular all multivariate polynomials. We also determine all univariate closure properties in the promise setting, and all multivariate closure properties under certain assumptions on the promise, in particular we determine all multivariate closure properties where the output vector lies on a monotone algebraic graph variety
Mechanisms of the drug penetration enhancer propylene glycol interacting with skin lipid membranes
Get PDFVery few drugs have the necessary physicochemical properties to cross the skin’s main permeability barrier, the stratum corneum (SC), in sufficient amounts. Propylene glycol (PG) is a chemical penetration enhancer that could be included in topical formulations in order to overcome the barrier properties of the skin and facilitate the transport of drugs across it. Experiments have demonstrated that PG increases the mobility and disorder of SC lipids and may extract cholesterol from the SC, but little is known about the molecular mechanisms of drug permeation enhancement by PG. In this work, we have performed molecular dynamics (MD) simulations to investigate the molecular-level effects of PG on the structure and properties of model SC lipid bilayers. The model bilayers were simulated in the presence of PG concentrations over the range of 0–100% w/w PG, using both an all-atom and a united atom force field. PG was found to localize in the hydrophilic headgroup regions at the bilayer interface, to occupy the lipid–water hydrogen-bonding sites, and to slightly increase lipid tail disorder in a concentration-dependent manner. We showed with MD simulation that PG enhances the permeation of small molecules such as water by interacting with the bilayer interface; the results of our study may be used to guide the design of formulations for transdermal drug delivery with enhanced skin permeation, as well as topical formulations and cosmetic products
Good inducing schemes for uniformly hyperbolic flows, and applications to exponential decay of correlations
Get PDFGiven an Axiom A attractor for a C1+α flow (α > 0), we construct a countable Markov extension with exponential return times
in such a way that the inducing set is a smoothly embedded unstable
disk. This avoids technical issues concerning irregularity of boundaries of
Markov partition elements and enables an elementary approach to certain questions involving exponential decay of correlations for SRB measures
Enhancing light transmission and thermal conduction for accelerating direct photo-thermal conversion and storage
No full textDirect absorption/storage solar collectors (DASSC) using composite phase change materials (CPCM) have attracted great attention in the solar energy field for the advantages of less heat exchange processes and high heat storage density. However, the low thermal conductivity of the CPCM has greatly restricted the thermal performance of the DASSC. This study aims to improve the photo-thermal conversion efficiency (PTCE) of DASSC using light transmission and thermal conduction enhancing methods within a new developed CPCM. Firstly, paraffin/expanded graphite CPCM is developed for direct solar absorption, conversion and storage. Secondly, both light transmission and thermal conduction enhancing methods have been investigated to improve the charging rate and PTCE of the solar collector. The paraffin/expanded graphite CPCM exhibits high absorbance in the visible light region with higher radiation energy, which is 3.03 times that of pure paraffin. At low irradiation intensity (400 W/m2), thermal conduction enhancing method performs better than light transmission enhancing method, in which the charging rate are increased by 15.64 % and 13.24 % compared to the non-enhanced collector, respectively. However, with irradiation intensity increase, such as 1000 W/m2, the light transmission enhancing method has a slightly better effect than the thermal conduction enhancing method, which increase the PTCE by 8.29 % and 8.25 %, respectively. This research introduces a new view to think about the method for improving the efficiency of DASSC
3D scanning a crime scene to enhance juror understanding of bloodstain pattern analysis evidence
Get PDFThere are numerous crime scene investigation applications of 3D scanning that have been previously documented. This paper documents the application of a 3D point cloud in the presentation of Bloodstain Pattern Analysis evidence to mock jurors. 150 mock jurors viewed a presentation of Bloodstain Pattern Analysis evidence from a murder trial in the UK. After viewing the evidence, the participants were tested on their knowledge of the evidence and repeated the test again 2 weeks later; to simulate criminal trial conditions; whereby there is a time lapse between the initial viewing of evidential material and deliberation. This paper found that the mock jurors who additionally viewed a 3D flythrough of a point cloud of the crime scene, better retained knowledge of the evidence over time, reported a greater ability to visualise the crime scene and had higher levels of interest in the evidence. Crucially, the 3D flythrough group did not report different levels of confidence in the accuracy of their memories of the evidence, nor different levels of emotional arousal to the group that viewed the evidence without the 3D presentation. Together, these findings suggest that 3D scanning of crime scenes, and the resultant point cloud’s presentation to jurors, could add further value to the justice system when spatial information, such as Bloodstain Pattern Analysis evidence, is presented
Speeding up inference of homologous recombination in bacteria
Get PDFBacteria reproduce clonally but most species recombine frequently, so that the ancestral process is best captured using an ancestral recombination graph. This graph model is often too complex to be used in an inferential setup, but it can be approximated for example by the ClonalOrigin model. Inference in the ClonalOrigin model is performed via a Reversible-Jump Markov Chain Monte Carlo algorithm, which attempts to jointly explore: the recombination rate, the number of recombination events, the departure and arrival points on the clonal genealogy for each recombination event, and the range of genomic sites affected by each recombination event. However, the Reversible-Jump algorithm often performs poorly due to the complexity of the target distribution since it needs to explore spaces of different dimensions. Recent developments in Bayesian computation methodology have provided ways to improve existing methods and code, but are not well-known outside the statistics community. We show how exploiting one of these new computational methods can lead to faster inference under the ClonalOrigin model