Sequential Monte Carlo methods for Bayesian elliptic inverse problems

In this article, we consider a Bayesian inverse problem associated to elliptic partial differential equations in two and three dimensions. This class of inverse problems is important in applications such as hydrology, but the complexity of the link function between unknown field and measurements can make it difficult to draw inference from the associated posterior. We prove that for this inverse problem a basic sequential Monte Carlo (SMC) method has a Monte Carlo rate of convergence with constants which are independent of the dimension of the discretization of the problem; indeed convergence of the SMC method is established in a function space setting. We also develop an enhancement of the SMC methods for inverse problems which were introduced in Kantas et al. (SIAM/ASA J Uncertain Quantif 2:464–489, 2014); the enhancement is designed to deal with the additional complexity of this elliptic inverse problem. The efficacy of the methodology and its desirable theoretical properties, are demonstrated for numerical examples in both two and three dimensions

Endovenous laser ablation therapy in children: applications and outcomes

BACKGROUND: Endovenous laser ablation is well recognized as the first-line treatment for superficial venous reflux with varicose veins in adults. It is not widely reported and is not an established practice in pediatric patients. OBJECTIVE: To illustrate a variety of pediatric venous conditions in which endovenous laser ablation can be utilized and to demonstrate its feasibility and safety in children. MATERIALS AND METHODS: We conducted a retrospective review of endovenous laser ablation procedures performed between January 2007 and July 2014 at two large pediatric institutions. RESULTS: We included 35 patients (17 males) who underwent endovenous laser ablation to 43 veins. Median age at first treatment was 14 years (range: 3-18 years). Median weight was 56 kg (range: 19-97 kg). Underlying diagnoses were common venous malformation (15), Klippel-Trenaunay syndrome (8), superficial venous reflux with varicose veins (5), verrucous hemangioma-related phlebectasia (4), venous varix (2) and arteriovenous fistula (1). The most common aim of treatment was to facilitate sclerotherapy. Thirty-four patients had treatment in the lower limbs and one patient in an upper limb. Ten of the veins treated with endovenous laser ablation had an additional procedure performed to close the vein. Complications attributable to endovenous laser ablation occurred in two patients (6%). One patient experienced post-procedural pain and one patient developed a temporary sensory nerve injury. Median clinical follow-up was 13 months (range: 28 days-5.7 years). The aim of the treatment was achieved in 29 of the 35 (83%) patients. CONCLUSION: Endovenous laser ablation is technically feasible and safe in children. It can be used in the management of a range of pediatric venous diseases with good outcomes

Accessing novel fluorinated heterocycles with the hypervalent fluoroiodane reagent by solution and mechanochemical synthesis

A new and efficient strategy for the rapid formation of novel fluorinated tetrahydropyridazines and dihydrooxazines has been developed by fluorocylisation of β,γ-unsaturated hydrazones and oximes with the hypervalent fluoroiodane reagent. Mechanochemical synthesis delivered fluorinated tetrahydropyridazines in similar excellent yields to conventional solution synthesis, whereas fluorinated dihydro-oxazines were prepared in much better yields by ball-milling

Pioneers in CNS inhibition: 2. Charles Sherrington and John Eccles on inhibition in spinal and supraspinal structures

This article reviews the contributions of the English neurophysiologist, Charles Scott Sherrington [1857–1952], and his Australian PhD trainee and collaborator, John Carew Eccles [1903–1997], to the concept of central inhibition in the spinal cord and brain. Both were awarded Nobel Prizes; Sherrington in 1932 for “discoveries regarding the function of neurons,” and Eccles in 1963 for “discoveries concerning the ionic mechanisms involved in excitation and inhibition in central portions of the nerve cell membrane.” Both spoke about central inhibition at their Nobel Prize Award Ceremonies. The subsequent publications of their talks were entitled “Inhibition as a coordinative factor” and “The ionic mechanism of postsynaptic inhibition”, respectively. Sherrington's work on central inhibition spanned 41 years (1893–1934), and for Eccles 49 years (1928–1977). Sherrington first studied central inhibition by observing hind limb muscle responses to electrical (peripheral nerve) and mechanical (muscle) stimulation. He used muscle length and force measurements until the early 1900s and electromyography in the late 1920s. Eccles used these techniques while working with Sherrington, but later employed extracellular microelectrode recording in the spinal cord followed in 1951 by intracellular recording from spinal motoneurons. This considerably advanced our understanding of central inhibition. Sherrington's health was poor during his retirement years but he nonetheless made a small number of largely humanities contributions up to 1951, one year before his death at the age of 94. In contrast, Eccles retained his health and vigor until 3 years before his death and published prolifically on many subjects during his 22 years of official retirement. His last neuroscience article appeared in 1994 when he was 91. Despite poor health he continued thinking about his life-long interest, the mind-brain problem, and was attempting to complete his autobiography in the last years of his life

CANFOR Portuguese version: validation study

This study is embedded in the larger project "Needs Assessment of the Mentally Disordered Prisoners" funded by Fundacao para a Ciencia e Tecnologia (PIC/IC/83257/2007). We acknowledge the General-Director for Prison Services for his authorization, the Prisons' Directors for their support, the medical and non-medical staff who collaborated in this study and detainees for their participation. Special thanks to Dr Ana Cabral for her support inside the prisons and Dr Jorge Pereira for his assistance in manuscript preparation. In memory of our late friend Dr Jose Morais, who collaborated on and supported this study from the beginning.BACKGROUND The increase in prisoner population is a troublesome reality in several regions of the world. Along with this growth there is increasing evidence that prisoners have a higher proportion of mental illnesses and suicide than the general population. In order to implement strategies that address criminal recidivism and the health and social status of prisoners, particularly in mental disordered offenders, it is necessary to assess their care needs in a comprehensive, but individual perspective. This assessment must include potential harmful areas like comorbid personality disorder, substance misuse and offending behaviours. The Camberwell Assessment of Need - Forensic Version (CANFOR) has proved to be a reliable tool designed to accomplish such aims. The present study aimed to validate the CANFOR Portuguese version. METHODS The translation, adaptation to the Portuguese context, back-translation and revision followed the usual procedures. The sample comprised all detainees receiving psychiatric care in four forensic facilities, over a one year period. A total of 143 subjects, and respective case manager, were selected. The forensic facilities were chosen by convenience: one prison hospital psychiatric ward (n=68; 47.6%), one male (n=24; 16.8%) and one female (n=22; 15.4%) psychiatric clinic and one civil security ward (n=29; 20.3%), all located nearby Lisbon. Basic descriptive statistics and Kappa weighted coefficients were calculated for the inter-rater and the test-retest reliability studies. The convergent validity was evaluated using the Global Assessment of Functioning and the Brief Psychiatric Rating Scale scores. RESULTS The majority of the participants were male and single, with short school attendance, and accused of a crime involving violence against persons. The most frequent diagnosis was major depression (56.1%) and almost half presented positive suicide risk. The reliability study showed average Kappa weighted coefficients of 0.884 and 0.445 for inter-rater and test-retest agreement, respectively. The convergent validity study presented highly significant correlations between unmet needs scores, GAF and BPRS scores. CONCLUSIONS The CANFOR Portuguese version revealed similar psychometric properties to the original English version. Moreover, the results of the reliability and validity studies indicate that the tool is appropriate for individual care needs assessment and as a guide for the mental health and social interventions in forensic psychiatric services.publishersversionpublishe

Patient-reported outcome measures for acne: a mixed-methods validation study (acne PROMs).

OBJECTIVES: To examine the acceptability and validity of two patient-reported outcome measures (PROMs) for adult acne, comparing them to the validated Acne-specific Quality of Life (Acne-QoL) measure. DESIGN: Mixed-methods validation study. SETTING: Participants were recruited by (1) mail-out through primary care if they had ever consulted for acne and received a prescription for acne treatment within the last 6 months, (2) opportunistically in secondary care and (3) poster advertisement in community venues. PARTICIPANTS: 221 (204 quantitative and 17 qualitative) participants with acne, aged 18-50 years. OUTCOME MEASURES: Quantitative sub-study participants completed Acne-QoL, Skindex-16 and Comprehensive Acne Quality of Life Scale (CompAQ) at baseline, 24 hours and 6 weeks. Qualitative sub-study participants took part in cognitive think-aloud interviews, while completing the same measures. Transcribed audio recordings were analysed using inductive thematic analysis. RESULTS: Quantitative analyses suggested high internal consistency (Cronbach's alpha 0.74-0.96) and reliability (intraclass correlation coefficient values 0.88-0.97) for both questionnaires. Both scales showed floor effects on some subdomains. Skindex-16 and CompAQ showed good evidence of construct validity when compared with Acne-QoL with Spearman's correlation coefficients 0.54-0.81, and good repeatability over 24 hours.Qualitative data uncovered wide-ranging views regarding usability and acceptability. Interviewees held strong but differing views about layout, question/response wording, redundant/similar questions and guidance notes. Similarly, interviewees differed in perceptions of acceptability of the different scales, particularly on relatability of questions and emotive reactions to scales. CONCLUSIONS: All PROMs performed well in statistical analyses. No PROM showed superior usability and acceptability in the qualitative study. Any PROM should be acceptable for further research in adult acne but researchers should consider the different domains and whether they will measure only facial or facial and trunk acne before making a selection. A new PROM or further evaluation of novel PROMs may be beneficial

A joint inversion of receiver function and Rayleigh wave phase velocity dispersion data to estimate crustal structure in West Antarctica

We determine crustal shear-wave velocity structure and crustal thickness at recently deployed seismic stations across West Antarctica, using a joint inversion of receiver functions and fundamental mode Rayleigh wave phase velocity dispersion. The stations are from both the UK Antarctic Network (UKANET) and Polar Earth Observing Network/Antarctic Network (POLENET/ANET). The former include, for the first time, 4 stations along the spine of the Antarctic Peninsula, 3 in the Ellsworth Land and 5 stations in the vicinity of the Pine Island Rift. Within the West Antarctic Rift System (WARS) we model a crustal thickness range of 18-28 km, and show that the thinnest crust (∼18 km) is in the vicinity of the Byrd Subglacial Basin and Bentley Subglacial Trench. In these regions we also find the highest ratio of fast (Vs = 4.0-4.3 km/s) (likely mafic) lower crust to felsic/intermediate upper crust. The thickest mafic lower crust we model is in Ellsworth Land, a critical area for constraining the eastern limits of the WARS. Although we find thinner crust in this region (∼30 km) than in the neighbouring Antarctic Peninsula and Haag-Ellsworth Whitmore block (HEW), the Ellsworth Land crust has not undergone as much extension as the central WARS. This suggests that the WARS does not link with the Weddell Sea Rift System through Ellsworth Land, and instead has progressed during its formation towards the Bellingshausen and Amundsen Sea Embayments. We also find that the thin WARS crust extends towards the Pine Island Rift, suggesting that the boundary between the WARS and the Thurston Island block lies in this region, ∼200 km north of its previously accepted position. The thickest crust (38-40 km) we model in this study is in the Ellsworth Mountain section of the HEW block. We find thinner crust (30-33 km) in the Whitmore Mountains and Haag Nunatak sectors of the HEW, consistent with the composite nature of the block. In the Antarctic Peninsula we find a crustal thickness range of 30-38 km and a likely dominantly felsic/intermediate crustal composition. By forward modelling high frequency receiver functions we also assess if any thick, low velocity subglacial sediment accumulations are present, and find a 0.1-0.8 km thick layer at 10 stations within the WARS, Thurston Island and Ellsworth Land. We suggest that these units of subglacial sediment could provide a source region for the soft basal till layers found beneath numerous outlet glaciers, and may act to accelerate ice flow

Systematic review of clinical practice guidelines for acne vulgaris published between January 2017 and July 2021

Background: Acne is very common, can cause considerable negative impact on quality of life and there is increasing concern over the use of long courses of oral antibiotics for this condition. Objectives: (1) To critically appraise reporting in acne guidelines and compare this with previous systematic review of acne guidelines. (2) Examine acne treatment guidance on pre-specified acne treatments of interest and compare between acne guidelines. Methods: Searches for new or updated guidelines were carried out in MEDLINE, Embase, Google Scholar, LILACS from 1 January 2017 to 31 July 2021, supplemented by searching a guideline-specific depository and checking for updates to guidelines included in previous review. We included guidelines, consensus statements or care protocols on the medical treatment of acne vulgaris in adults and/or children and excluded those that focused on a single intervention or subgroup of acne, regional adaptations of guidelines or guidelines included in previous review. AGREE II checklist was applied to critically appraise reporting of guidelines. Results were synthesised narratively. Results: Of 807 abstracts identified nine guidelines were identified that were eligible for inclusion. All guidelines had AGREE II scores above average in at least one domain and reporting was substantially improved compared to the systematic review of acne carried out 5 years previously. There was consensus between guidelines on the key role of topical treatments as first-line acne treatment and most recommended continuing topical treatments as maintenance therapy. There was considerable variation between guidelines on classification of severity, indications for commencing oral antibiotics and on maximum duration of oral antibiotics. However, there was consensus on the need for co-prescription of a non-antibiotic topical treatment when using oral antibiotics. There were notable differences on recommendations regarding provision of information for patients on how to use topical treatments or how to mitigate against side effects. Conclusions: Substantial differences in classification of acne severity hampered comparisons between guidelines. Although development and reporting of guidelines has improved over the past 5 years, differences in key recommendations remain, possibly reflecting uncertainties in the underlying evidence base. Differences between guidelines could have substantial implications for prevalence of antibiotic prescribing for acne

Quality and readability of online patient information regarding sclerotherapy for venous malformations

BACKGROUND: Patients often use the internet as a source of information about their condition and treatments. However, this information is unregulated and varies in quality. OBJECTIVE: To evaluate the readability and quality of online information for pediatric and adult patients and caregivers regarding sclerotherapy for venous malformations. MATERIALS AND METHODS: “Venous malformation sclerotherapy” was entered into Google, and results were reviewed until 20 sites that satisfied predefined inclusion criteria were identified. Scientific and non-patient-focused web pages were excluded. Readability was assessed using the Flesch Reading Ease Score and American Medical Association reading difficulty recommendations and quality was assessed using Journal of the American Medical Association standards and assessing if the site displayed HONcode (Health on the Net Code) certification. Assessment of the breadth of relevant information was made using a predefined checklist. RESULTS: Forty-nine search engine results were reviewed before 20 sites were identified for analysis. Average Flesch Reading Ease Score was 44 (range: 24.2–70.1), representing a “fairly difficult” reading level. None of the sites had a Flesch Reading Ease Score meeting the American Medical Association recommendation of 80-90. Only one site met all four Journal of the American Medical Association quality criteria (average: 2.1). None of the sites displayed a HONcode seal. The information most frequently found was: sclerotherapy is performed by radiologists, multiple treatments may be needed and surgery is an alternative treatment. CONCLUSION: Online information regarding sclerotherapy for venous malformations is heterogeneous in quality and breadth of information, and does not meet readability recommendations for patient information. Radiologists should be aware of and account for this when meeting patients

Prediction of the yield of grains through artificial intelligence

Grass turns out to be an appropriate food for cattle, mainly in tropical climate countries such as Latin American countries. This is due to the high number of species that can be used, the possibility of growing them year-round, the ability of the ruminant to use fibrous supplies and be an economic source (Sánchez et al., Data mining and big data. DMBD 2018. Lecture notes in computer science, vol 10943. Springer, Cham, 2018, [1]). In this work, an application of neural networks was carried out in the forecasting of more accurate values of production and quality of grasslands