Calibration strategies for use of the nanoDot OSLD in CT applications.

Aluminum oxide based optically stimulated luminescent dosimeters (OSLD) have been recognized as a useful dosimeter for measuring CT dose, particularly for patient dose measurements. Despite the increasing use of this dosimeter, appropriate dosimeter calibration techniques have not been established in the literature; while the manufacturer offers a calibration procedure, it is known to have relatively large uncertainties. The purpose of this work was to evaluate two clinical approaches for calibrating these dosimeters for CT applications, and to determine the uncertainty associated with measurements using these techniques. Three unique calibration procedures were used to calculate dose for a range of CT conditions using a commercially available OSLD and reader. The three calibration procedures included calibration (a) using the vendor-provided method, (b) relative to a 120 kVp CT spectrum in air, and (c) relative to a megavoltage beam (implemented with 60 Co). The dose measured using each of these approaches was compared to dose measured using a calibrated farmer-type ion chamber. Finally, the uncertainty in the dose measured using each approach was determined. For the CT and megavoltage calibration methods, the dose measured using the OSLD nanoDot was within 5% of the dose measured using an ion chamber for a wide range of different CT scan parameters (80-140 kVp, and with measurements at a range of positions). When calibrated using the vendor-recommended protocol, the OSLD measured doses were on average 15.5% lower than ion chamber doses. Two clinical calibration techniques have been evaluated and are presented in this work as alternatives to the vendor-provided calibration approach. These techniques provide high precision for OSLD-based measurements in a CT environment

Editorial

Alexander Kluge, avocat de formation, écrivain, philosophe, cinéaste et producteur de télévision, a développé une œuvre multiple et foisonnante, tant sur le plan de la fiction que de la théorie critique (il est proche d’Adorno qui lui avait conseillé d’investir le medium du film). Porte-parole du nouveau cinéma allemand (il est l’un des signataires et instigateurs du manifeste d’Oberhausen), ses films de fiction et ses documentaires ont marqué le renouvellement de la forme du « film-essai ». ..

Have e-cigarettes renormalised or displaced youth smoking? Results of a segmented regression analysis of repeated cross-sectional survey data in England, Scotland and Wales

Objectives: To examine whether during a period of limited e-cigarette regulation and rapid growth in their use, smoking began to become renormalised among young people. Design: Interrupted time-series analysis of repeated cross-sectional time-series data. Setting: Great Britain Participants: 248 324 young people aged approximately 13 and 15 years, from three national surveys during the years 1998–2015. Intervention Unregulated growth of e-cigarette use (following the year 2010, until 2015). Outcome measures: Primary outcomes were prevalence of self-reported ever smoking and regular smoking. Secondary outcomes were attitudes towards smoking. Tertiary outcomes were ever use of cannabis and alcohol. Results: In final models, no significant change was detected in the pre-existing trend for ever smoking (OR 1.01, CI 0.99 to 1.03). There was a marginally significant slowing in the rate of decline for regular smoking (OR 1.04, CI 1.00 to 1.08), accompanied by a larger slowing in the rate of decline of cannabis use (OR 1.21, CI 1.18 to 1.25) and alcohol use (OR 1.17, CI 1.14 to 1.19). In all models and subgroup analyses for smoking attitudes, an increased rate of decline was observed after 2010 (OR 0.88, CI 0.86 to 0.90). Models were robust to sensitivity analyses. Conclusions: There was a marginal slowing in the decline in regular smoking during the period following 2010, when e-cigarettes were emerging but relatively unregulated. However, these patterns were not unique to tobacco use and the decline in the acceptability of smoking behaviour among youth accelerated during this time. These analyses provide little evidence that renormalisation of youth smoking was occurring during a period of rapid growth and limited regulation of e-cigarettes from 2011 to 2015

Bites by exotic snakes reported to the UK National Poisons Information Service 2009-2020

Introduction: Snakebite is recognised as a neglected tropical disease and a cause of substantial morbidity and mortality. Whilst the most medically important snakes are typically native of Asia, Africa, Latin America and Oceania, the possibility of encountering these snakes is no longer limited by geography due to an increasing number of exotic (non-native) snakes being held in captivity. Methods: A retrospective review of snakebite enquiries to the UK National Poisons Information Service (NPIS) between 2009 and 2020. Enquiries about the European adder (Vipera berus) or where the identity of the snake was unknown were excluded. Results: There were 321 exotic snakebites in 300 patients involving 68 different species during this period. Ten patients were bitten on more than one occasion. The majority of patients (64.5%) were male. Most bites were inflicted by snakes of the family Colubridae (184/321, 57.3%); seventeen bites resulted in moderate symptoms (predominantly swelling of the bitten limb). There were 30 (9.3%) bites by Viperidae and 14 (4.3%) bites by Elapidae. All severe cases (n = 15) resulted from bites by either Viperidae (n = 10) or Elapidae (n = 5). Antivenom was given in 17 cases. One fatality was recorded. Conclusions: Despite their low incidence, exotic snakebites present a substantial challenge for UK healthcare professionals. Although rare, these bites typically occur in individuals (usually male) who keep snakes as part of their occupation or hobby and are therefore at risk of multiple bites. Bites can result in venom hypersensitisation and the risk of venom-induced anaphylaxis. Rapid access to expert clinical advice is available in the UK on a 24-hour basis through the National Poisons Information Service and is strongly recommended in all cases of exotic snakebite

Measuring Height Change Around the Periphery of the Greenland Ice Sheet With Radar Altimetry

This work is licensed under a Creative Commons Attribution 4.0 International License.Ice loss measurements around the periphery of the Greenland Ice Sheet can provide key information on the response to climate change. Here we use the excellent spatial and temporal coverage provided by the European Space Agency (ESA) CryoSat satellite, together with NASA airborne Operation IceBridge and automatic weather station data, to study the influence of changing conditions on the bias between the height estimated by the satellite radar altimeter and the ice sheet surface. Surface and near-surface conditions on the ice sheet periphery change with season and geographic position in a way that affects the returned altimeter waveform and can therefore affect the estimate of the surface height derived from the waveform. Notwithstanding the possibility of a varying bias between the derived and real surface, for the lower accumulation regions in the western and northern ice sheet periphery (<∼1 m snow accumulation yearly) we show that the CryoSat altimeter can measure height change throughout the year, including that associated with ice dynamics, summer melt and winter accumulation. Further, over the 9-year CryoSat lifetime it is also possible to relate height change to change in speed of large outlet glaciers, for example, there is significant height loss upstream of two branches of the Upernavik glacier in NW Greenland that increased in speed during this time, but much less height loss over a third branch that slowed in the same time period. In contrast to the west and north, winter snow accumulation in the south-east periphery can be 2–3 m and the average altimeter height for this area can decrease by up to 2 m during the fall and winter when the change in the surface elevation is much smaller. We show that vertical downward movement of the dense layer from the last summer melt, coupled with overlying dry snow, is responsible for the anomalous altimeter height change. However, it is still possible to estimate year-to-year height change measurements in this area by using data from the late-summer to early fall when surface returns dominate the altimeter signal

Investigating marker accuracy in differentiating between university scripts written by students and those produced using ChatGPT

The introduction of OpenAI’s ChatGPT has widely been considered a turning point for assessment in higher education. Whilst we find ourselves on the precipice of a profoundly disruptive technology, generative artificial intelligence (AI) is here to stay. At present, institutions around the world are considering how best to respond to such new and emerging tools, ranging from outright bans to re-evaluating assessment strategies. In evaluating the extent of the problem that these tools pose to the marking of assessments, a study was designed to investigate marker accuracy in differentiating between scripts prepared by students and those produced using generative AI. A survey containing undergraduate reflective writing scripts and postgraduate extended essays was administered to markers at a medical school in Wales, UK. The markers were asked to assess the scripts on writing style and content, and to indicate whether they believed the scripts to have been produced by students or ChatGPT. Of the 34 markers recruited, only 23% and 19% were able to correctly identify the ChatGPT undergraduate and postgraduate scripts, respectively. A significant effect of suspected script authorship was found for script content, X²(4, n=34) = 10.41, p<0.05, suggesting that written content holds clues as to how markers assign authorship. We recommend consideration be given to how generative AI can be responsibly integrated into assessment strategies and expanding our definition of what constitutes academic misconduct in light of this new technology

Glacier velocities and dynamic ice discharge from the Queen Elizabeth Islands, Nunavut, Canada

Recent studies indicate an increase in glacier mass loss from the Canadian Arctic Archipelago as a result of warmer summer air temperatures. However, no complete assessment of dynamic ice discharge from this region exists. We present the first complete surface velocity mapping of all ice masses in the Queen Elizabeth Islands and show that these ice masses discharged ~2.6 ± 0.8 Gt a−1 of ice to the oceans in winter 2012. Approximately 50% of the dynamic discharge was channeled through non surge-type Trinity and Wykeham Glaciers alone. Dynamic discharge of the surge-type Mittie Glacier varied from 0.90 ± 0.09 Gt a−1 during its 2003 surge to 0.02 ± 0.02 Gt a−1 during quiescence in 2012, highlighting the importance of surge-type glaciers for interannual variability in regional mass loss. Queen Elizabeth Islands glaciers currently account for ~7.5% of reported dynamic discharge from Arctic ice masses outside Greenland.We thank NSERC, Canada Foundation for Innovation, Ontario Research Fund, ArcticNet, Ontario Graduate Scholarship, University of Ottawa and the NSERC Canada Graduate Scholarship for funding. RADARSAT-2 data were provided by MacDonald, Dettwiler and Associates under the RADARSAT-2 Government Data Allocation administrated by the Canadian Space Agency. Support to DB is provided through the Climate Change Geosciences Program, Earth Sciences Sector, Natural Resources Canada (ESS Contribution #20130293). We also acknowledge support from U.K NERC for grants R3/12469 and NE/K004999 to JAD.This is the accepted version of an article published in Geophysical Research Letters. An edited version of this paper was published by AGU. Copyright (2014) American Geophysical Union. The final version is available at http://onlinelibrary.wiley.com/doi/10.1002/2013GL058558/abstract;jsessionid=6A3AD907C4383DA5D4E20C4924D6EC18.f02t02

Targeted genetic testing for familial hypercholesterolaemia using next generation sequencing:a population-based study

Background&lt;p&gt;&lt;/p&gt; Familial hypercholesterolaemia (FH) is a common Mendelian condition which, untreated, results in premature coronary heart disease. An estimated 88% of FH cases are undiagnosed in the UK. We previously validated a method for FH mutation detection in a lipid clinic population using next generation sequencing (NGS), but this did not address the challenge of identifying index cases in primary care where most undiagnosed patients receive healthcare. Here, we evaluate the targeted use of NGS as a potential route to diagnosis of FH in a primary care population subset selected for hypercholesterolaemia.&lt;p&gt;&lt;/p&gt; Methods&lt;p&gt;&lt;/p&gt; We used microfluidics-based PCR amplification coupled with NGS and multiplex ligation-dependent probe amplification (MLPA) to detect mutations in LDLR, APOB and PCSK9 in three phenotypic groups within the Generation Scotland: Scottish Family Health Study including 193 individuals with high total cholesterol, 232 with moderately high total cholesterol despite cholesterol-lowering therapy, and 192 normocholesterolaemic controls.&lt;p&gt;&lt;/p&gt; Results&lt;p&gt;&lt;/p&gt; Pathogenic mutations were found in 2.1% of hypercholesterolaemic individuals, in 2.2% of subjects on cholesterol-lowering therapy and in 42% of their available first-degree relatives. In addition, variants of uncertain clinical significance (VUCS) were detected in 1.4% of the hypercholesterolaemic and cholesterol-lowering therapy groups. No pathogenic variants or VUCS were detected in controls.&lt;p&gt;&lt;/p&gt; Conclusions&lt;p&gt;&lt;/p&gt; We demonstrated that population-based genetic testing using these protocols is able to deliver definitive molecular diagnoses of FH in individuals with high cholesterol or on cholesterol-lowering therapy. The lower cost and labour associated with NGS-based testing may increase the attractiveness of a population-based approach to FH detection compared to genetic testing with conventional sequencing. This could provide one route to increasing the present low percentage of FH cases with a genetic diagnosis