Size matters : seeing the values in large technology heritage

Large technology heritage objects are impressive, exciting and fascinating. They can also be difficult, dangerous and expensive. When working with large technology objects every project demands more resources, every triumph is more newsworthy and every mistake is more visible. With large technology objects “getting it right” is vital. This thesis explores what “getting it right” means in both affective and practical terms, and for both producers of, and visitors to, large technology heritage displays. During 2008-9 over 80 producers and 368 visitors were interviewed at seven heritage sites and, for comparison, one non-heritage site within Australia. These interviews were analysed both qualitatively and quantitatively to examine people’s attitudes to large technology heritage, and to understand the major influences that form, maintain and change such attitudes. The thesis also examines methods of interpreting and displaying large technology objects, as well as the impact of heritage industry standards on the preservation, restoration and management of large technology heritage. The results of the study indicate that, while the practical challenges of giving big, old machines a new life as heritage are formidable, it is the values that different people see in such objects that are the source of the greatest difficulties. Producers of large technology heritage come from different backgrounds and communities of practice, and they see different values in the objects and look to different practical ways to enhance those values. Unfortunately they do not always understand, or value, each other’s values, which can lead to bitter disputes over which is the right way to do things. They also do not always understand the values that their visitors see in the objects, or recognise that display methods that are welcoming and engaging for their visitors may be very different from the ways in which they themselves expect to see large technology objects presented. The major finding of this study, therefore, is that an emphasis on developing technical methods of preserving, restoring and interpreting large technology heritage is doomed to failure unless it is combined with an equally strong emphasis on developing methods to draw out and reconcile the different values that people see in that heritage. Different practical methods of preserving, restoring and interpreting large technology objects are not “right” or “wrong” in themselves, but they do have the effect of enhancing some values and reducing or destroying others. Unless everyone involved in the project agrees on the values that practical treatments should enhance, there will be no consensus about the success of those treatments. The findings of this study have important implications for research and practice in large technology heritage. In particular, research is needed into the social impacts of large technology heritage, and into ways of incorporating values effectively into the practice of caring for large technology heritage. Such research, and concomitant changes in practice, will contribute significantly to the success and sustainability of large technology projects, and to the survival of these fabulous objects for the future

Treating the untreatable in art and heritage materials: Ultrafast laser cleaning of "cloth-of-gold"

Laser cleaning provides art and heritage conservators with an alternative means to restore objects when traditional chemical and mechanical methods are not viable. However, long (>nanosecond) laser pulses can cause unwanted damage from photothermal processes and provide limited control over ablation depth. Ultrashort (<picosecond) pulse lasers are emerging as a more appropriate tool for cleaning historic artifacts because of their unique ability to avoid heat- and shock-wave generation, thus minimizing collateral damage of the underlayers, and to remove material with near-nanometer precision. Here we demonstrate the effectiveness of ultrashort pulses by cleaning 19th century military gold braid without any detrimental effects on the gold foil or the underlying silk thread structure. The results are compared with nanosecond-pulse laser treatment that damages the surface structure. By introducing in situ feedback control of the laser ablation via laser-induced breakdown spectroscopy (LIBS) monitoring of the ablated plume, we are able to halt the cleaning process just as the contaminant layer is completely removed. This technique allows ultrafast laser ablation to extend the armory of conservation treatments, enabling restoration of a range of complex and fragile heritage objects previously untreatable by conventional means

Comparative genomics of Campylobacter jejuni from clinical campylobacteriosis stool specimens

Background: Campylobacter jejuni is a pervasive pathogen of major public health concern with a complex ecology requiring accurate and informative approaches to define pathogen diversity during outbreak investigations. Source attribution analysis may be confounded if the genetic diversity of a C. jejuni population is not adequately captured in a single specimen. The aim of this study was to determine the genomic diversity of C. jejuni within individual stool specimens from four campylobacteriosis patients. Direct plating and pre-culture filtration of one stool specimen per patient was used to culture multiple isolates per stool specimen. Whole genome sequencing and pangenome level analysis were used to investigate genomic diversity of C. jejuni within a patient. Results: A total 92 C. jejuni isolates were recovered from four patients presenting with gastroenteritis. The number of isolates ranged from 13 to 30 per patient stool. Three patients yielded a single C. jejuni multilocus sequence type: ST-21 (n = 26, patient 4), ST-61 (n = 30, patient 1) and ST-2066 (n = 23, patient 2). Patient 3 was infected with two different sequence types [ST-51 (n = 12) and ST-354 (n = 1)]. Isolates belonging to the same sequence type from the same patient specimen shared 12–43 core non-recombinant SNPs and 0–20 frameshifts with each other, and the pangenomes of each sequence type consisted of 1406–1491 core genes and 231–264 accessory genes. However, neither the mutation nor the accessory genes were connected to a specific functional gene category. Conclusions: Our findings show that the C. jejuni population recovered from an individual patient’s stool are genetically diverse even within the same ST and may have shared common ancestors before specimens were obtained. The population is unlikely to have evolved from a single isolate at the time point of initial patient infection, leading us to conclude that patients were likely infected with a heterogeneous C. jejuni population. The diversity of the C. jejuni population found within individual stool specimens can inform future methodological approaches to attribution and outbreak investigations

Microevolution during the emergence of a monophasic Salmonella Typhimurium epidemic in the United Kingdom

Microevolutionary events associated with the emergence and clonal expansion of new 27 epidemic clones of bacterial pathogens hold the key to understanding the drivers of 28 epidemiological success. We describe a comparative whole genome sequence and 29 phylogenomic analysis of monophasic Salmonella Typhimurium isolates from the UK 30 and Italy from 2005-2012. Monophasic isolates from this time formed a single clade 31 distinct from recent monophasic epidemic clones described previously from North 32 America and Spain. The current UK monophasic epidemic clones encode a novel 33 genomic island encoding resistance to heavy metals (SGI-3), and composite transposon 34 encoding antibiotic resistance genes not present in other Typhimurium isolates, that 35 may have contributed to the epidemiological success. We also report a remarkable 36 degree of genotypic variation that accumulated during clonal expansion of a UK 37 epidemic including multiple independent acquisitions of a novel prophage carrying the 38 sopE gene and multiple deletion events affecting the phase II flagellin locus

High Campylobacter diversity in retail chicken: Epidemiologically important strains may be missed with current sampling methods

Campylobacter spp. are leading bacterial gastroenteritis pathogens. Infections are largely underreported, and the burden of outbreaks may be underestimated. Current strategies of testing as few as one isolate per sample can affect attribution of cases to epidemiologically important sources with high Campylobacter diversity, such as chicken meat. Multiple culture method combinations were utilized to recover and sequence Campylobacter from 45 retail chicken samples purchased across Norwich, UK, selecting up to 48 isolates per sample. Simulations based on resampling were used to assess the impact of Campylobacter sequence type (ST) diversity on outbreak detection. Campylobacter was recovered from 39 samples (87%), although only one sample was positive through all broth, temperature, and plate combinations. Three species were identified (Campylobacter jejuni, Campylobacter coli, and Campylobacter lari), and 33% of samples contained two species. Positive samples contained 1-8 STs. Simulation revealed that up to 87 isolates per sample would be required to detect 95% of the observed ST diversity, and 26 isolates would be required for the average probability of detecting a random theoretical outbreak ST to reach 95%. An optimized culture approach and selecting multiple isolates per sample are essential for more complete Campylobacter recovery to support outbreak investigation and source attribution

Characterization of a pESI-like plasmid and analysis of multidrug-resistant Salmonella enterica Infantis isolates in England and Wales

Salmonella enterica serovar Infantis is the fifth most common Salmonella serovar isolated in England and Wales. Epidemiological, genotyping and antimicrobial-resistance data for S. enterica Infantis isolates were used to analyse English and Welsh demographics over a 5 year period. Travel cases associated with S. enterica Infantis were mainly from Asia, followed by cases from Europe and North America. Since 2000, increasing numbers of S. enterica Infantis had multidrug resistance determinants harboured on a large plasmid termed ‘plasmid of emerging S. enterica Infantis’ (pESI). Between 2013 and 2018, 42 S. enterica Infantis isolates were isolated from humans and food that harboured resistance determinants to multiple antimicrobial classes present on a pESI-like plasmid, including extended-spectrum β-lactamases (ESBLs; blaCTX-M-65). Nanopore sequencing of an ESBL-producing human S. enterica Infantis isolate indicated the presence of two regions on an IncFIB pESI-like plasmid harbouring multiple resistance genes. Phylogenetic analysis of the English and Welsh S. enterica Infantis population indicated that the majority of multidrug-resistant isolates harbouring the pESI-like plasmid belonged to a single clade maintained within the population. The blaCTX-M-65 ESBL isolates first isolated in 2013 comprise a lineage within this clade, which was mainly associated with South America. Our data, therefore, show the emergence of a stable resistant clone that has been in circulation for some time in the human population in England and Wales, highlighting the necessity of monitoring resistance in this serovar

Cultura Material, Cultura Científica: Património Industrial para o Futuro

IH4Future (PTDC/FIS-aQM/30292/2017Material, Culture, Scientific Culture: Industrial Heritage for the Futurepublishersversionpublishe

Argon redistribution during a metamorphic cycle: Consequences for determining cooling rates

40Ar/39Ar thermochronology is commonly used to constrain the rates and times of cooling in exhumed metamorphic terranes, with ages usually linked to temperature via Dodson's closure temperature (TC) formulation. Whilst many metamorphic 40Ar/39Ar data are consistent with the timing of crystallisation or cooling within a chronological framework defined by other, higher temperature, chronometers, other 40Ar/39Ar data are more difficult to interpret. We report white mica and biotite single grain fusion and laser ablation 40Ar/39Ar ages from felsic gneisses from the Western Gneiss Region, Norway. The rocks record isothermal decompression from peak eclogite-facies conditions (white mica stable) to amphibolite-facies conditions (biotite stable) at c. 700 °C. White mica and biotite yield dispersed single grain fusion dates from 416 to 373 Ma and 437 to 360 Ma respectively. In-situ laser ablation analyses provide a similar range, with white mica spot ages ranging from 424 to 370 Ma and biotite spot ages ranging from 437 to 370 Ma. The dates span the duration of the metamorphic cycle suggested by previous studies, and cannot be reconciled with the results of simple models of Ar loss by diffusion during cooling. Samples that show evidence for different physical processes, such as the chemical breakdown of white mica, partial melting, and fluid ingress, generated different age populations to samples that did not experience or record obvious petrological evidence for these processes. Samples that record significant recrystallization and deformation yielded younger white mica (but older biotite) single grain fusion ages than more pristine samples. Amphibolite-facies gneisses that preserve evidence for significant partial melting generated younger biotite ages than samples that recorded evidence for significant hydration. Our data support other reported observations that high-temperature metamorphic mica 40Ar/39Ar dates cannot be assumed to record the timing of cooling through a specific temperature window. Careful assessment of the petrographic context of the dated minerals and consideration of their post-crystallisation history may provide a more robust insight into whether ‘age’ links to ‘stage’ in a temporally meaningful way

CoronaHiT: high-throughput sequencing of SARS-CoV-2 genomes.

We present CoronaHiT, a platform and throughput flexible method for sequencing SARS-CoV-2 genomes (≤ 96 on MinION or > 96 on Illumina NextSeq) depending on changing requirements experienced during the pandemic. CoronaHiT uses transposase-based library preparation of ARTIC PCR products. Method performance was demonstrated by sequencing 2 plates containing 95 and 59 SARS-CoV-2 genomes on nanopore and Illumina platforms and comparing to the ARTIC LoCost nanopore method. Of the 154 samples sequenced using all 3 methods, ≥ 90% genome coverage was obtained for 64.3% using ARTIC LoCost, 71.4% using CoronaHiT-ONT and 76.6% using CoronaHiT-Illumina, with almost identical clustering on a maximum likelihood tree. This protocol will aid the rapid expansion of SARS-CoV-2 genome sequencing globally.The sequencing costs were funded by the COVID-19 Genomics UK (COG-UK) Consortium which is supported by funding from the Medical Research Council (MRC) part of UK Research & Innovation (UKRI), the National Institute of Health Research (NIHR) and Genome Research Limited, operating as the Wellcome Sanger Institute