The effect of hydrogen sulphide on ammonium bisulphite when used as an oxygen scavenger in aqueous solutions

Peer reviewedPostprin

Ionospheric Power-Spectrum Tomography in Radio Interferometry

A tomographic method is described to quantify the three-dimensional power-spectrum of the ionospheric electron-density fluctuations based on radio-interferometric observations by a two-dimensional planar array. The method is valid to first-order Born approximation and might be applicable to correct observed visibilities for phase variations due to the imprint of the full three-dimensional ionosphere. It is shown that not the ionospheric electron density distribution is the primary structure to model in interferometry, but its autocorrelation function or equivalent its power-spectrum. An exact mathematical expression is derived that provides the three dimensional power-spectrum of the ionospheric electron-density fluctuations directly from a rescaled scattered intensity field and an incident intensity field convolved with a complex unit phasor that depends on the w-term and is defined on the full sky pupil plane. In the limit of a small field of view, the method reduces to the single phase screen approximation. Tomographic self-calibration can become important in high-dynamic range observations at low radio frequencies with wide-field antenna interferometers, because a three-dimensional ionosphere causes a spatially varying convolution of the sky, whereas a single phase screen results in a spatially invariant convolution. A thick ionosphere can therefore not be approximated by a single phase screen without introducing errors in the calibration process. By applying a Radon projection and the Fourier projection-slice theorem, it is shown that the phase-screen approach in three dimensions is identical to the tomographic method. Finally we suggest that residual speckle can cause a diffuse intensity halo around sources, due to uncorrectable ionospheric phase fluctuations in the short integrations, which could pose a fundamental limit on the dynamic range in long-integration images.Comment: 8 pages; Accepted for publication in Ap

Likelihood of aneurysmal subarachnoid haemorrhage in patients with normal unenhanced CT, CSF xanthochromia on spectrophotometry and negative CT angiography

Peer reviewedPublisher PD

Death from cancer:frequent unscheduled care

Funding: SEEM is funded through a Clinical Academic Fellowship from the Chief Scientist Office (CAF_17_06). Funding for data extraction and storage was through PATCH Scotland and Tayside Oncology Research Foundation Research Grants.OBJECTIVE : To examine the demographic, clinical, and temporal factors associated with cancer decedents being a frequent or very frequent unscheduled care (GP-general practice Out-Of-Hours (GPOOH) and Accident & Emergency (A&E)) attender, in their last year of life. METHODS : Retrospective cohort study, of all 2443 cancer decedents in Tayside, Scotland, over 30- months period up to 06/2015, comparing frequent attenders (5-9 attendances/year) and very frequent attenders (≥10 attendances/year) to infrequent attenders (1-4 attendances/year) and non-attenders. Clinical and demographic datasets were linked to routinely-collected clinical data using the Community Health Index number. Anonymised linked data were analysed in SafeHaven, using binary/multinomial logistic regression, and Generalised Estimating Equations analysis. RESULTS : Frequent attenders were more likely to be older, and have upper gastrointestinal (GI), haematological, breast and ovarian malignancies, and less likely to live in accessible areas or have a late cancer diagnosis. They were more likely to use GPOOH than A&E, less likely to have face-to-face unscheduled care attendances, and less likely to be admitted to hospital following unscheduled care attendance. CONCLUSIONS : Age, cancer type, accessibility and timing of diagnosis relative to death were associated with increased likelihood of being a frequent or very frequent attender at unscheduled care.Publisher PDFPeer reviewe

Community prescribing trends and prevalence in the last year of life, for people who die from cancer

Funding: SM is funded through a Clinical Academic Fellowship (CAF_17_06) from the Chief Scientist Office. PATCH Scotland and Tayside Oncology Research Foundation Research Grants funded data extraction and storage costs. Publication costs were funded by the University of St Andrews.Background People who die from cancer (‘cancer decedents’) may latterly experience unpleasant and distressing symptoms. Prescribing medication for pain and symptom control is essential for good-quality palliative care; however, such provision is variable, difficult to quantify and poorly characterised in current literature. This study aims to characterise trends in prescribing analgesia, non-analgesic palliative care medication and non-palliative medications, to cancer decedents, in their last year of life, and to assess any associations with demographic or clinical factors. Methods This descriptive study, analysed all 181,247 prescriptions issued to a study population of 2443 cancer decedents in Tayside, Scotland (2013–2015), in the last year of life, linking prescribing data to demographic, and cancer registry datasets using the unique patient-identifying Community Health Index (CHI) number. Anonymised linked data were analysed in Safe Haven using chi-squared test for trend, binary logistic regression and Poisson regression in SPSSv25. Results In their last year of life, three in four cancer decedents were prescribed strong opioids. Two-thirds of those prescribed opioids were also prescribed laxatives and/or anti-emetics. Only four in ten cancer decedents were prescribed all medications in the ‘Just in Case’ medication categories and only one in ten was prescribed breakthrough analgesia in the last year of life. The number of prescriptions for analgesia and palliative care drugs increased in the last 12 weeks of life. The number of prescriptions for non-palliative care medications, including anti-hypertensives, statins and bone protection, decreased over the last year, but was still substantial. Cancer decedents who were female, younger, or had lung cancer were more likely to be prescribed strong opioids; however, male cancer decedents had higher odds of being prescribed breakthrough analgesia. Cancer decedents who had late diagnoses had lower odds of being prescribed strong opioids. Conclusions A substantial proportion of cancer decedents were not prescribed strong opioids, breakthrough medication, or medication to alleviate common palliative care symptoms (including ‘Just in Case’ medication). Many patients continued to be prescribed non-palliative care medications in their last days and weeks of life. Age, gender, cancer type and timing of diagnosis affected patients’ odds of being prescribed analgesic and non-analgesic palliative care medication.Publisher PDFPeer reviewe

Improving Lunar Exploration with Robotic Follow-up

We are investigating how augmenting human field work with subsequent robot activity can improve lunar exploration. Robotic "follow-up" might involve: completing geology observations; making tedious or long-duration measurements of a target site or feature; curating samples in-situ; and performing unskilled, labor-intensive work. To study this technique, we have begun conducting a series of lunar analog field tests at Haughton Crater (Canada). Motivation: In most field geology studies on Earth, explorers often find themselves left with a set of observations they would have liked to make, or samples they would have liked to take, if only they had been able to stay longer in the field. For planetary field geology, we can imagine mobile robots - perhaps teleoperated vehicles previously used for manned exploration or dedicated planetary rovers - being deployed to perform such follow-up activities [1]

Thermal Stability of RP-2 for Hydrocarbon Boost Regenerative Cooling

A series of tests were performed in the NASA Glenn Research Centers Heated Tube Facility to study the heat transfer and thermal stability behavior of RP-2 under conditions similar to those found in rocket engine cooling channels. It has long been known that hydrocarbon fuels, such as RP-2, can decompose at high temperature to form deposits (coke) which can adversely impact rocket engine cooling channel performance. The heated tube facility provides a simple means to study these effects. Using resistively heated copper tubes in a vacuum chamber, flowing RP-2 was heated to explore thermal effects at a range of test conditions. Wall temperature (850-1050F) and bulk fluid temperature (300-500F) were varied to define thermal decomposition and stability at each condition. Flow velocity and pressure were fixed at 75 fts and 1000 psia, respectively. Additionally, five different batches of RP-2 were tested at identical conditions to examine any thermal stability differences resulting from batch to batch compositional variation. Among these tests was one with a potential coke reducing additive known as 1,2,3,4-Tetrahydroquinoline (THQ). While copper tubes were used for the majority of tests, two exploratory tests were performed with a copper alloy known as GRCop-42. Each tube was instrumented with 15 thermocouples to examine the temperature profile, and carbon deposition at each thermocouple location was determined post-test in an oxidation furnace. In many tests, intermittent local temperature increases were observed visually and in the thermocouple data. These hot spots did not appear to correspond with a higher carbon deposition

Prospecting for Polar Volatiles: Results from the Resolve Field

Both the Moon and Mercury evidently host ice and other volatile compounds in cold traps at the planets poles. Determining the form, spatial distribution, and abundance of these volatiles at the lunar poles can help us understand how and when they were delivered and emplaced. This bears directly on the delivery of water and prebiotic compounds to the inner planets over the solar system s history, and also informs plans for utilizing the volatiles as resources for sustained human exploration as well as the commercial development of space. Temperature models and orbital data suggest near-surface volatile concentrations may exist at polar locations not strictly in permanent shadow. Remote operation of a robotic lunar rover mission for the 7-10 days of available sunlight would permit key questions to be answered. But such a short, quick-tempo mission has unique challenges and requires a new concept of operations. Both science and rover operations decisionmaking must be done in real time, requiring immediate situational awareness, data analysis, and decision support tools

Biomarker testing in oncology - Requirements for organizing external quality assessment programs to improve the performance of laboratory testing:revision of an expert opinion paper on behalf of IQNPath ABSL

In personalized medicine, predictive biomarker testing is the basis for an appropriate choice of therapy for patients with cancer. An important tool for laboratories to ensure accurate results is participation in external quality assurance (EQA) programs. Several providers offer predictive EQA programs for different cancer types, test methods, and sample types. In 2013, a guideline was published on the requirements for organizing high-quality EQA programs in molecular pathology. Now, after six years, steps were taken to further harmonize these EQA programs as an initiative by IQNPath ABSL, an umbrella organization founded by various EQA providers. This revision is based on current knowledge, adds recommendations for programs developed for predictive biomarkers by in situ methodologies (immunohistochemistry and in situ hybridization), and emphasized transparency and an evidence-based approach. In addition, this updated version also has the aim to give an overview of current practices from various EQA providers