High resolution spectral characteristics of the Earth-ionosphere cavity resonances

The natural resonances of the Earth-ionosphere cavity at frequencies between 5 and 100 Hz have been studied since the fundamental paper by Schumann. While the gross features of the phenomena are now well understood, considerable work remains to be done on their detailed behaviour. In the present study a high resolution, data adaptive spectral technique is applied to digital electromagnetic data obtained at a moderate latitude. A particular feature of the method employed is that spectral properties become available on the same time scale as many ELF events, thus both time local and time averaged resonance features can be readily established. The technique can thus be applied to both dynamic and steady-state descriptions of the cavity's properties. For the data set considered, the technique adequately resolves the first six resonance modes on a time scale of 0.75 s. The presence of higher order modes is also indicated. The time averaged frequencies obtained are in accord with those of previous experimental determinations. When the time local properties of individual transient waveforms are examined, however, we observe a number of detailed effects which are predicted by theory. The precise spectral structure of the resonance modes appears influenced by the differing locations of the sources of transient excitation. In the case of the first order resonance mode, the properties of the cavity consistently support both singlet and doublet resonance behaviour

Audiomagnetotelluric sounding using the Schumann resonances

The Schumann resonance waveforms in the lower ELF band (5-100 Hz) are produced within the Earth-ionosphere cavity by distant lightning discharges; they provide a useful source field for shallow audiomagnetotclluric (AMT) crustal sounding. In this study we investigate their waveform characteristics that are important to the assumptions of AMT sounding. A time-domain polarization analysis technique is applied to a variety of examples of Schumann resonance waveforms. The multiplicity of worldwide thunderstorm centres provides a background activity which is generally incoherent and, accordingly, displays incoherent polarization characteristics. Superimposed on the back­ground are larger-amplitude transient events (sferics) from individual thunderstorm centres; they represent the response of the Earth-ionosphere cavity to very large lightning discharges and are generally linearly polarized at a given azimuth. The analysis indicates that the Schuman resonance waveforms provide a plane-wave source field, as required for electromagnetic crustal sounding. The differences in the "received" characteristics between the two waveform types prompted an investigation of the extent to which the waveform type and its particular polarization characteristics influence the determination of a geoelectric sounding curve. A detailed study, carried out with a multivariate maximum entropy spectral analysis algorithm, indicates that the two types of Schumann resonance waveform provide repeatable and consistent results at the 95% confidence level and that the linear polarizations associated with the sferics do not influence the estimation of the Earth response

Non-destructive evaluation of cement-based materials from pressure-stimulated electrical emission - Preliminary results

This is the post-print version of the final paper published in Construction and Building Materials. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2010 Elsevier B.V.This paper introduces the possibility of in situ assessment of loading and remaining strength in concrete structures by means of measuring discharge of electric current from loaded specimens. The paper demonstrates that the techniques have been applied to other rock-like materials, but that for the first time they are applied to cement-based materials and a theoretical model is proposed in relation to the appearance of electrical signals during sample loading and up to fracture. A series of laboratory experiments on cement mortar specimens in simple uniaxial compression, and subsequently in bending – hence displaying both tension and compression – are described and show clear correlations between resulting strains and currents measured. Under uniaxial loading there is a well-defined relationship between the pressure-stimulated current (PSC) as a result of a monotonic mechanical loading regime. Similar results are observed in the three-point bending tests where a range of loading regimes is studied, including stepped changes in loading. While currents can be measured at low strains, best results seem to be obtained when strains approach and exceed yield stress values. This technique clearly has immense potential for structural health monitoring of cement-based structures. Both intermittent and continuous monitoring becomes possible, and given an ongoing campaign of monitoring, remaining strength can be estimated

Investigation of genetically regulated gene expression and response to treatment in rheumatoid arthritis highlights an association between IL18RAP expression and treatment response.

This article has been accepted for publication in Annals of the Rheumatic Diseases, 2020 following peer review, and the Version of Record can be accessed online at http://dx.doi.org/10.1136/annrheumdis-2020-217204OBJECTIVES: In this study, we sought to investigate whether there was any association between genetically regulated gene expression (as predicted using various reference panels) and anti-tumour necrosis factor (anti-TNF) treatment response (change in erythrocyte sedimentation rate (ESR)) using 3158 European ancestry patients with rheumatoid arthritis. METHODS: The genetically regulated portion of gene expression was estimated in the full cohort of 3158 subjects (as well as within a subcohort consisting of 1575 UK patients) using the PrediXcan software package with three different reference panels. Estimated expression was tested for association with anti-TNF treatment response. As a replication/validation experiment, we also investigated the correlation between change in ESR with measured gene expression at the Interleukin 18 Receptor Accessory Protein (IL18RAP) gene in whole blood and synovial tissue, using an independent replication data set of patients receiving conventional synthetic disease modifying anti-rheumatic drugs, with directly measured (via RNA sequencing) gene expression. RESULTS: We found that predicted expression of IL18RAP showed a consistent signal of association with treatment response across the reference panels. In our independent replication data set, IL18RAP expression in whole blood showed correlation with the change in ESR between baseline and follow-up (r=-0.35, p=0.0091). Change in ESR was also correlated with the expression of IL18RAP in synovial tissue (r=-0.28, p=0.02). CONCLUSION: Our results suggest that IL18RAP expression is worthy of further investigation as a potential predictor of treatment response in rheumatoid arthritis that is not specific to a particular drug type

Non-destructive Techniques Methodologies for the Detection of Ancient Structures under Heritage Buildings

[EN] Structures and elements buried beneath heritage buildings are frequent but are often unknown and inaccessible. Therefore, they are difficult to locate in general if an archaeological excavation is not carried out, with the economic cost and time involved. It is important to discover them in order to increase our knowledge of cultural heritage, as well as to know, recover and improve the state of conservation of the materials that make up these structures. This paper presents methodologies for locating old structures using a low-cost NDT approach, with a qualitative and quantitative analysis of GPR profiles in heritage buildings. Small perforations are performed at critical points and introducing an endoscope for verification. Various crypts have been located using the proposed methodologies in a real study case: The Church of the Asución of Llíria in Spain.Gil Benso, E.; Mas Tomas, MDLA.; Lerma Elvira, C.; Torner, ME.; Vercher Sanchis, J. (2021). Non-destructive Techniques Methodologies for the Detection of Ancient Structures under Heritage Buildings. International journal of architectural heritage (electronic). 15(10):1457-1473. https://doi.org/10.1080/15583058.2019.1700320S14571473151

Quality of treatment and surgical approach for rectal gastrointestinal stromal tumour (GIST) in a large European cohort

Background: Rectal gastrointestinal stromal tumours (GISTs) are rare tumours. Variability in the managementmay influence outcome, but there is a lack of understanding regarding contemporary variancein care. A multicenter, international, retrospective cohort study was performed to elucidate characteristicsand outcomes of rectal GIST in European practice, with particular reference to surgical approach.Methods: All rectal GIST patients diagnosed between 2009 and 2018 were identified from five Europeandatabases. Recurrence free survival (RFS) and overall survival (OS) were estimated using Kaplan-Meiermethod. Possible confounders were identified using Cox regression analyses.Results: From 210 patients, 155 patients had surgery. The three main types of surgery were local tumourresection (LTR, n ¼ 46), low anterior resection (LAR, n ¼ 31) and abdomino-perineal resection (APR,n ¼ 32). Most patients received neoadjuvant (65%) and/or adjuvant imatinib therapy (66%). Localrecurrence rate after surgery was 15% and overall recurrence rate 28%. No significant differences werefound in terms of RFS nor OS between LTR, LAR and APR. However, locally resected tumours weresmaller, while LAR and APR patients more often received perioperative imatinib. General hospitalstreated smaller GISTs, offered imatinib less frequently, and had a higher tumour rupture rate. In the multivariate analysis in the group having LTR, APR or LAR, the only significant prognostic factor for localrecurrence was higher age (HR 1.06, CI 1.00e1.12, p ¼ 0.048).Conclusions: In European clinical practice for rectal GIST, LTR, LAR and APR have comparable localcontrol. Multimodal approach is higher and tumour rupture less frequent in specialist centres comparedto general hospitals.Experimentele farmacotherapi